diff --git a/include/xlnt/cell/cell_type.hpp b/include/xlnt/cell/cell_type.hpp
index a307a2de..cee0e48b 100644
--- a/include/xlnt/cell/cell_type.hpp
+++ b/include/xlnt/cell/cell_type.hpp
@@ -37,18 +37,22 @@ namespace xlnt {
 /// </summary>
 enum class XLNT_API cell_type
 {
-    /// no value. note: this is different from an empty string value or 0 numeric value
-    null,
-    /// number
-    numeric,
-    /// string
-    string,
-    /// value is a formula
-    formula,
+    /// no value
+    empty,
+    /// value is TRUE or FALSE
+    boolean,
+    /// value is an ISO 8601 formatted date
+    date,
     /// value is a known error code such as \#VALUE!
     error,
-    /// value is TRUE or FALSE
-    boolean
+    /// value is a string stored in the cell
+    inline_string,
+    /// value is a number
+    number,
+    /// value is a string shared with other cells to save space
+    shared_string,
+    /// value is the string result of a formula
+    formula_string
 };
 
 } // namespace xlnt
diff --git a/include/xlnt/workbook/workbook.hpp b/include/xlnt/workbook/workbook.hpp
index 01826e88..f879be08 100644
--- a/include/xlnt/workbook/workbook.hpp
+++ b/include/xlnt/workbook/workbook.hpp
@@ -699,9 +699,9 @@ public:
     /// Append a shared string to the shared string collection in this workbook.
     /// This should not generally be called unless you know what you're doing.
     /// If allow_duplicates is false and the string is already in the collection,
-    /// it will not be added.
+    /// it will not be added. Returns the index of the added string.
     /// </summary>
-    void add_shared_string(const rich_text &shared, bool allow_duplicates = false);
+    std::size_t add_shared_string(const rich_text &shared, bool allow_duplicates = false);
 
     /// <summary>
     /// Returns a reference to the shared strings being used by cells
diff --git a/source/cell/cell.cpp b/source/cell/cell.cpp
index 3d3c9cba..09f4b121 100644
--- a/source/cell/cell.cpp
+++ b/source/cell/cell.cpp
@@ -194,12 +194,12 @@ cell::cell(detail::cell_impl *d)
 
 bool cell::garbage_collectible() const
 {
-    return !(data_type() != type::null || is_merged() || has_formula() || has_format());
+    return !(has_value() || is_merged() || has_formula() || has_format());
 }
 
 void cell::value(std::nullptr_t)
 {
-    d_->type_ = type::null;
+    clear_value();
 }
 
 void cell::value(bool boolean_value)
@@ -211,82 +211,56 @@ void cell::value(bool boolean_value)
 void cell::value(int int_value)
 {
     d_->value_numeric_ = static_cast<long double>(int_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(unsigned int int_value)
 {
     d_->value_numeric_ = static_cast<long double>(int_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(long long int int_value)
 {
     d_->value_numeric_ = static_cast<long double>(int_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(unsigned long long int int_value)
 {
     d_->value_numeric_ = static_cast<long double>(int_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(float float_value)
 {
     d_->value_numeric_ = static_cast<long double>(float_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(double float_value)
 {
     d_->value_numeric_ = static_cast<long double>(float_value);
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(long double d)
 {
     d_->value_numeric_ = d;
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
 }
 
 void cell::value(const std::string &s)
 {
-    auto checked = check_string(s);
-
-    if (checked.size() > 1 && checked.front() == '=')
-    {
-        d_->type_ = type::formula;
-        formula(checked);
-    }
-    else if (cell::error_codes().find(checked) != cell::error_codes().end())
-    {
-        error(checked);
-    }
-    else
-    {
-        d_->type_ = type::string;
-        d_->value_text_.plain_text(checked);
-
-        if (checked.size() > 0)
-        {
-            workbook().add_shared_string(d_->value_text_);
-        }
-    }
+    value(rich_text(check_string(s)));
 }
 
 void cell::value(const rich_text &text)
 {
-    if (text.runs().size() == 1 && !text.runs().front().second.is_set())
-    {
-        value(text.plain_text());
-    }
-    else
-    {
-        d_->type_ = type::string;
-        d_->value_text_ = text;
-        workbook().add_shared_string(text);
-    }
+    check_string(text.plain_text());
+
+    d_->type_ = type::shared_string;
+    d_->value_numeric_ = static_cast<long double>(workbook().add_shared_string(text));
 }
 
 void cell::value(const char *c)
@@ -306,28 +280,28 @@ void cell::value(const cell c)
 
 void cell::value(const date &d)
 {
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
     d_->value_numeric_ = d.to_number(base_date());
     number_format(number_format::date_yyyymmdd2());
 }
 
 void cell::value(const datetime &d)
 {
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
     d_->value_numeric_ = d.to_number(base_date());
     number_format(number_format::date_datetime());
 }
 
 void cell::value(const time &t)
 {
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
     d_->value_numeric_ = t.to_number();
     number_format(number_format::date_time6());
 }
 
 void cell::value(const timedelta &t)
 {
-    d_->type_ = type::numeric;
+    d_->type_ = type::number;
     d_->value_numeric_ = t.to_number();
     number_format(xlnt::number_format("[hh]:mm:ss"));
 }
@@ -354,7 +328,7 @@ bool cell::is_merged() const
 
 bool cell::is_date() const
 {
-    return data_type() == type::numeric && has_format() && number_format().is_date_format();
+    return data_type() == type::number && has_format() && number_format().is_date_format();
 }
 
 cell_reference cell::reference() const
@@ -429,6 +403,8 @@ void cell::formula(const std::string &formula)
     {
         d_->formula_ = formula;
     }
+
+    data_type(type::number);
     
     worksheet().register_calc_chain_in_manifest();
 }
@@ -551,7 +527,7 @@ void cell::clear_value()
 {
     d_->value_numeric_ = 0;
     d_->value_text_.clear();
-    d_->type_ = cell::type::null;
+    d_->type_ = cell::type::empty;
     clear_formula();
 }
 
@@ -666,18 +642,23 @@ void cell::protection(const class protection &protection_)
 template <>
 XLNT_API std::string cell::value() const
 {
-    return d_->value_text_.plain_text();
+    return value<rich_text>().plain_text();
 }
 
 template <>
 XLNT_API rich_text cell::value() const
 {
+    if (data_type() == cell::type::shared_string)
+    {
+        return workbook().shared_strings().at(static_cast<std::size_t>(d_->value_numeric_));
+    }
+
     return d_->value_text_;
 }
 
 bool cell::has_value() const
 {
-    return d_->type_ != cell::type::null;
+    return d_->type_ != cell::type::empty;
 }
 
 std::string cell::to_string() const
@@ -686,12 +667,13 @@ std::string cell::to_string() const
 
     switch (data_type())
     {
-    case cell::type::null:
+    case cell::type::empty:
         return "";
-    case cell::type::numeric:
+    case cell::type::number:
         return nf.format(value<long double>(), base_date());
-    case cell::type::string:
-    case cell::type::formula:
+    case cell::type::inline_string:
+    case cell::type::shared_string:
+    case cell::type::formula_string:
     case cell::type::error:
         return nf.format(value<std::string>());
     case cell::type::boolean:
@@ -731,17 +713,29 @@ void cell::value(const std::string &value_string, bool infer_type)
 {
     value(value_string);
 
-    if (!infer_type)
+    if (!infer_type || value_string.empty())
     {
         return;
     }
 
+    if (value_string.front() == '=' && value_string.size() > 1)
+    {
+        formula(value_string);
+        return;
+    }
+
+    if (value_string.front() == '#' && value_string.size() > 1)
+    {
+        error(value_string);
+        return;
+    }
+
     auto percentage = cast_percentage(value_string);
 
     if (percentage.first)
     {
         d_->value_numeric_ = percentage.second;
-        d_->type_ = cell::type::numeric;
+        d_->type_ = cell::type::number;
         number_format(xlnt::number_format::percentage());
     }
     else
@@ -750,7 +744,7 @@ void cell::value(const std::string &value_string, bool infer_type)
 
         if (time.first)
         {
-            d_->type_ = cell::type::numeric;
+            d_->type_ = cell::type::number;
             number_format(number_format::date_time6());
             d_->value_numeric_ = time.second.to_number();
         }
@@ -761,7 +755,7 @@ void cell::value(const std::string &value_string, bool infer_type)
             if (numeric.first)
             {
                 d_->value_numeric_ = numeric.second;
-                d_->type_ = cell::type::numeric;
+                d_->type_ = cell::type::number;
             }
         }
     }
diff --git a/source/detail/implementations/cell_impl.cpp b/source/detail/implementations/cell_impl.cpp
index a1bddb92..900da4e4 100644
--- a/source/detail/implementations/cell_impl.cpp
+++ b/source/detail/implementations/cell_impl.cpp
@@ -29,7 +29,12 @@ namespace xlnt {
 namespace detail {
 
 cell_impl::cell_impl()
-    : type_(cell_type::null), parent_(nullptr), column_(1), row_(1), is_merged_(false), value_numeric_(0)
+    : type_(cell_type::empty),
+      parent_(nullptr),
+      column_(1),
+      row_(1),
+      is_merged_(false),
+      value_numeric_(0)
 {
 }
 
diff --git a/source/detail/serialization/xlsx_consumer.cpp b/source/detail/serialization/xlsx_consumer.cpp
index b9b557c9..b356dcd2 100644
--- a/source/detail/serialization/xlsx_consumer.cpp
+++ b/source/detail/serialization/xlsx_consumer.cpp
@@ -1407,8 +1407,6 @@ void xlsx_consumer::read_worksheet(const std::string &rel_id)
     read_namespaces();
 
     xlnt::range_reference full_range;
-
-    const auto &shared_strings = target_.shared_strings();
     auto &manifest = target_.manifest();
 
     const auto workbook_rel = manifest.relationship(path("/"), relationship_type::office_document);
@@ -1699,15 +1697,20 @@ void xlsx_consumer::read_worksheet(const std::string &rel_id)
 
                     if (has_value)
                     {
-                        if (type == "inlineStr" || type == "str")
+                        if (type == "str")
                         {
-                            cell.value(value_string);
+                            cell.d_->value_text_ = value_string;
+                            cell.data_type(cell::type::formula_string);
                         }
-                        else if (type == "s" && !has_formula)
+                        else if (type == "inlineStr")
                         {
-                            auto shared_string_index = static_cast<std::size_t>(std::stoull(value_string));
-                            auto shared_string = shared_strings.at(shared_string_index);
-                            cell.value(shared_string);
+                            cell.d_->value_text_ = value_string;
+                            cell.data_type(cell::type::inline_string);
+                        }
+                        else if (type == "s")
+                        {
+                            cell.d_->value_numeric_ = std::stold(value_string);
+                            cell.data_type(cell::type::shared_string);
                         }
                         else if (type == "b") // boolean
                         {
diff --git a/source/detail/serialization/xlsx_producer.cpp b/source/detail/serialization/xlsx_producer.cpp
index 84a6a491..8ab586aa 100644
--- a/source/detail/serialization/xlsx_producer.cpp
+++ b/source/detail/serialization/xlsx_producer.cpp
@@ -777,7 +777,7 @@ void xlsx_producer::write_shared_string_table(const relationship & /*rel*/)
             while (current_cell.column() <= dimension.bottom_right().column())
             {
                 if (ws.has_cell(current_cell)
-                    && ws.cell(current_cell).data_type() == cell::type::string)
+                    && ws.cell(current_cell).data_type() == cell::type::shared_string)
                 {
                     ++string_count;
                 }
@@ -2145,10 +2145,9 @@ void xlsx_producer::write_worksheet(const relationship &rel)
     }
 
     std::unordered_map<std::string, std::string> hyperlink_references;
+    std::vector<cell_reference> cells_with_comments;
 
     write_start_element(xmlns, "sheetData");
-    const auto &shared_strings = ws.workbook().shared_strings();
-    std::vector<cell_reference> cells_with_comments;
 
     for (auto row : ws.rows())
     {
@@ -2206,122 +2205,124 @@ void xlsx_producer::write_worksheet(const relationship &rel)
             }
         }
 
-        for (auto cell : row)
+        for (auto cell : row) // CT_Cell
         {
+            if (cell.garbage_collectible()) continue;
+
+            // record data about the cell needed later
+
             if (cell.has_comment())
             {
                 cells_with_comments.push_back(cell.reference());
             }
 
-            if (!cell.garbage_collectible())
+            if (cell.has_hyperlink())
             {
-                write_start_element(xmlns, "c");
-                write_attribute("r", cell.reference().to_string());
+                hyperlink_references[cell.reference().to_string()] = reverse_hyperlink_references[cell.hyperlink()];
+            }
 
-                if (cell.has_format())
+            write_start_element(xmlns, "c");
+
+            // begin cell attributes
+
+            write_attribute("r", cell.reference().to_string());
+
+            if (cell.has_format())
+            {
+                write_attribute("s", cell.format().d_->id);
+            }
+
+            switch (cell.data_type())
+            {
+            case cell::type::boolean:
+                write_attribute("t", "b");
+                break;
+
+            case cell::type::date:
+                write_attribute("t", "d");
+                break;
+
+            case cell::type::error:
+                write_attribute("t", "e");
+                break;
+
+            case cell::type::inline_string:
+                write_attribute("t", "inlineStr");
+                break;
+
+            case cell::type::number:
+                write_attribute("t", "n");
+                break;
+
+            case cell::type::shared_string:
+                write_attribute("t", "s");
+                break;
+
+            case cell::type::formula_string:
+                write_attribute("t", "str");
+                break;
+            }
+
+            //write_attribute("cm", "");
+            //write_attribute("vm", "");
+            //write_attribute("ph", "");
+
+            // begin child elements
+
+            if (cell.has_formula())
+            {
+                write_element(xmlns, "f", cell.formula());
+            }
+
+            switch (cell.data_type())
+            {
+            case cell::type::boolean:
+                write_element(xmlns, "v", write_bool(cell.value<bool>()));
+                break;
+
+            case cell::type::date:
+                write_element(xmlns, "v", cell.value<std::string>());
+                break;
+
+            case cell::type::error:
+                write_element(xmlns, "v", cell.value<std::string>());
+                break;
+
+            case cell::type::inline_string:
+                write_start_element(xmlns, "is");
+                // TODO: make a write_rich_text method and use that here
+                write_element(xmlns, "t", cell.value<std::string>());
+                write_end_element(xmlns, "is");
+                break;
+
+            case cell::type::number:
+                write_start_element(xmlns, "v");
+
+                if (is_integral(cell.value<long double>()))
                 {
-                    write_attribute("s", cell.format().d_->id);
-                }
-
-                if (cell.has_hyperlink())
-                {
-                    hyperlink_references[cell.reference().to_string()] = reverse_hyperlink_references[cell.hyperlink()];
-                }
-
-                if (cell.data_type() == cell::type::string)
-                {
-                    if (cell.has_formula())
-                    {
-                        write_attribute("t", "str");
-                        write_element(xmlns, "f", cell.formula());
-                        write_element(xmlns, "v", cell.to_string());
-                        write_end_element(xmlns, "c");
-
-                        continue;
-                    }
-
-                    int match_index = -1;
-
-                    for (std::size_t i = 0; i < shared_strings.size(); i++)
-                    {
-                        if (shared_strings[i] == cell.value<rich_text>())
-                        {
-                            match_index = static_cast<int>(i);
-                            break;
-                        }
-                    }
-
-                    if (match_index == -1)
-                    {
-                        if (cell.value<std::string>().empty())
-                        {
-                            write_attribute("t", "s");
-                        }
-                        else
-                        {
-                            write_attribute("t", "inlineStr");
-                            write_start_element(xmlns, "is");
-                            write_element(xmlns, "t", cell.value<std::string>());
-                            write_end_element(xmlns, "is");
-                        }
-                    }
-                    else
-                    {
-                        write_attribute("t", "s");
-                        write_element(xmlns, "v", match_index);
-                    }
+                    write_characters(static_cast<std::ptrdiff_t>(cell.value<long double>()));
                 }
                 else
                 {
-                    if (cell.data_type() != cell::type::null)
-                    {
-                        if (cell.data_type() == cell::type::boolean)
-                        {
-                            write_attribute("t", "b");
-                            write_element(xmlns, "v", write_bool(cell.value<bool>()));
-                        }
-                        else if (cell.data_type() == cell::type::numeric)
-                        {
-                            if (cell.has_formula())
-                            {
-                                write_element(xmlns, "f", cell.formula());
-                                write_element(xmlns, "v", cell.to_string());
-                                write_end_element(xmlns, "c");
-
-                                continue;
-                            }
-
-                            write_attribute("t", "n");
-                            write_start_element(xmlns, "v");
-
-                            if (is_integral(cell.value<long double>()))
-                            {
-                                write_characters(cell.value<long long int>());
-                            }
-                            else
-                            {
-                                std::stringstream ss;
-                                ss.precision(20);
-                                ss << cell.value<long double>();
-                                ss.str();
-                                write_characters(ss.str());
-                            }
-
-                            write_end_element(xmlns, "v");
-                        }
-                    }
-                    else if (cell.has_formula())
-                    {
-                        write_element(xmlns, "f", cell.formula());
-                        // todo (but probably not) could calculate the formula and set the value here
-                        write_end_element(xmlns, "c");
-
-                        continue;
-                    }
+                    std::stringstream ss;
+                    ss.precision(20);
+                    ss << cell.value<long double>();
+                    write_characters(ss.str());
                 }
 
-                write_end_element(xmlns, "c");
+                write_end_element(xmlns, "v");
+                break;
+
+            case cell::type::shared_string:
+                write_element(xmlns, "v", static_cast<std::size_t>(cell.d_->value_numeric_));
+                break;
+
+            case cell::type::formula_string:
+                write_element(xmlns, "v", cell.value<std::string>());
+                break;
             }
+
+            write_end_element(xmlns, "c");
         }
 
         write_end_element(xmlns, "row");
diff --git a/source/workbook/workbook.cpp b/source/workbook/workbook.cpp
index f51e63a4..60c22538 100644
--- a/source/workbook/workbook.cpp
+++ b/source/workbook/workbook.cpp
@@ -1285,20 +1285,29 @@ const std::vector<rich_text> &workbook::shared_strings() const
     return d_->shared_strings_;
 }
 
-void workbook::add_shared_string(const rich_text &shared, bool allow_duplicates)
+std::size_t workbook::add_shared_string(const rich_text &shared, bool allow_duplicates)
 {
     register_workbook_part(relationship_type::shared_string_table);
 
+    auto index = std::size_t(0);
+
     if (!allow_duplicates)
     {
         // TODO: inefficient, use a set or something?
         for (auto &s : d_->shared_strings_)
         {
-            if (s == shared) return;
+            if (s == shared)
+            {
+                return index;
+            }
+
+            ++index;
         }
     }
 
     d_->shared_strings_.push_back(shared);
+
+    return index;
 }
 
 bool workbook::contains(const std::string &sheet_title) const
diff --git a/source/worksheet/worksheet.cpp b/source/worksheet/worksheet.cpp
index 9533afe3..9e0b8804 100644
--- a/source/worksheet/worksheet.cpp
+++ b/source/worksheet/worksheet.cpp
@@ -553,7 +553,7 @@ void worksheet::merge_cells(const range_reference &reference)
 
             if (!first)
             {
-                if (cell.data_type() == cell::type::string)
+                if (cell.data_type() == cell::type::shared_string)
                 {
                     cell.value("");
                 }
@@ -672,7 +672,7 @@ bool worksheet::compare(const worksheet &other, bool reference) const
                 return false;
             }
 
-            if (this_cell.data_type() == xlnt::cell::type::numeric
+            if (this_cell.data_type() == xlnt::cell::type::number
                 && std::fabs(this_cell.value<long double>() - other_cell.value<long double>()) > 0.L)
             {
                 return false;
diff --git a/tests/cell/cell_test_suite.hpp b/tests/cell/cell_test_suite.hpp
index 6d344016..7b79d1fe 100644
--- a/tests/cell/cell_test_suite.hpp
+++ b/tests/cell/cell_test_suite.hpp
@@ -121,7 +121,7 @@ private:
         auto ws = wb.active_sheet();
         auto cell = ws.cell(xlnt::cell_reference("A", 1));
 
-        xlnt_assert(cell.data_type() == xlnt::cell::type::null);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::empty);
         xlnt_assert(cell.column() == "A");
         xlnt_assert(cell.row() == 1);
         xlnt_assert(cell.reference() == "A1");
@@ -134,12 +134,12 @@ private:
 
         const auto datatypes =
         {
-            xlnt::cell::type::null,
+            xlnt::cell::type::empty,
             xlnt::cell::type::boolean,
             xlnt::cell::type::error,
-            xlnt::cell::type::formula,
-            xlnt::cell::type::numeric,
-            xlnt::cell::type::string
+            xlnt::cell::type::formula_string,
+            xlnt::cell::type::number,
+            xlnt::cell::type::shared_string
         };
 
         for (const auto &datatype : datatypes)
@@ -150,7 +150,7 @@ private:
             cell.data_type(datatype);
             xlnt_assert(cell.data_type() == datatype);
             cell.clear_value();
-            xlnt_assert(cell.data_type() == xlnt::cell::type::null);
+            xlnt_assert(cell.data_type() == xlnt::cell::type::empty);
         }
     }
 
@@ -161,13 +161,13 @@ private:
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
         cell.value("hello");
-        xlnt_assert(cell.data_type() == xlnt::cell::type::string);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::shared_string);
 
         cell.value(".");
-        xlnt_assert(cell.data_type() == xlnt::cell::type::string);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::shared_string);
 
         cell.value("0800");
-        xlnt_assert(cell.data_type() == xlnt::cell::type::string);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::shared_string);
     }
 
     void test_formula1()
@@ -177,7 +177,8 @@ private:
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
         cell.value("=42", true);
-        xlnt_assert(cell.data_type() == xlnt::cell::type::formula);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
+        xlnt_assert(cell.has_formula());
     }
 
     void test_formula2()
@@ -187,7 +188,8 @@ private:
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
         cell.value("=if(A1<4;-1;1)", true);
-        xlnt_assert(cell.data_type() == xlnt::cell::type::formula);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
+        xlnt_assert(cell.has_formula());
     }
 
     void test_formula3()
@@ -213,8 +215,8 @@ private:
         auto ws = wb.active_sheet();
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
-        cell.value("=");
-        xlnt_assert(cell.data_type() == xlnt::cell::type::string);
+        cell.value("=", true);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::shared_string);
         xlnt_assert(cell.value<std::string>() == "=");
         xlnt_assert(!cell.has_formula());
     }
@@ -253,7 +255,7 @@ private:
 
         cell.value(xlnt::datetime(2010, 7, 13, 6, 37, 41));
 
-        xlnt_assert(cell.data_type() == xlnt::cell::type::numeric);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
         xlnt_assert_delta(cell.value<long double>(), 40372.27616898148L, 1E-9);
         xlnt_assert(cell.is_date());
         xlnt_assert(cell.number_format().format_string() == "yyyy-mm-dd h:mm:ss");
@@ -266,7 +268,7 @@ private:
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
         cell.value(xlnt::date(2010, 7, 13));
-        xlnt_assert(cell.data_type() == xlnt::cell::type::numeric);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
         xlnt_assert(cell.value<long double>() == 40372.L);
         xlnt_assert(cell.is_date());
         xlnt_assert(cell.number_format().format_string() == "yyyy-mm-dd");
@@ -279,7 +281,7 @@ private:
         auto cell = ws.cell(xlnt::cell_reference(1, 1));
 
         cell.value(xlnt::time(1, 3));
-        xlnt_assert(cell.data_type() == xlnt::cell::type::numeric);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
         xlnt_assert_delta(cell.value<long double>(), 0.04375L, 1E-9);
         xlnt_assert(cell.is_date());
         xlnt_assert(cell.number_format().format_string() == "h:mm:ss");
@@ -355,7 +357,7 @@ private:
         cell.value(xlnt::timedelta(1, 3, 0, 0, 0));
 
         xlnt_assert(cell.value<long double>() == 1.125);
-        xlnt_assert(cell.data_type() == xlnt::cell::type::numeric);
+        xlnt_assert(cell.data_type() == xlnt::cell::type::number);
         xlnt_assert(!cell.is_date());
         xlnt_assert(cell.number_format().format_string() == "[hh]:mm:ss");
     }
diff --git a/tests/worksheet/worksheet_test_suite.hpp b/tests/worksheet/worksheet_test_suite.hpp
index 0d79fa69..9998ba3d 100644
--- a/tests/worksheet/worksheet_test_suite.hpp
+++ b/tests/worksheet/worksheet_test_suite.hpp
@@ -313,7 +313,7 @@ public:
         auto ws = wb.active_sheet();
         xlnt::cell cell = ws[xlnt::cell_reference("A1")];
         xlnt_assert_equals(cell.reference().to_string(), "A1");
-        xlnt_assert_equals(cell.data_type(), xlnt::cell::type::null);
+        xlnt_assert_equals(cell.data_type(), xlnt::cell::type::empty);
     }
 
     void test_setitem()