diff --git a/src/MiniExcel.OpenXml/Styles/Builder/DefaultSheetStyleBuilder.cs b/src/MiniExcel.OpenXml/Styles/Builder/DefaultSheetStyleBuilder.cs
index aa6f6073..d5b368b0 100644
--- a/src/MiniExcel.OpenXml/Styles/Builder/DefaultSheetStyleBuilder.cs
+++ b/src/MiniExcel.OpenXml/Styles/Builder/DefaultSheetStyleBuilder.cs
@@ -496,13 +496,13 @@ protected override async Task GenerateCellXfAsync()
         await NewWriter.WriteEndElementAsync().ConfigureAwait(false);
 
         /*
-         * <x:xf numFmtId="21" fontId="0" fillId="0" borderId="1" xfId="0" applyNumberFormat="1" applyFill="1" applyBorder="1" applyAlignment="1" applyProtection="1">
+         * <x:xf numFmtId="46" fontId="0" fillId="0" borderId="1" xfId="0" applyNumberFormat="1" applyFill="1" applyBorder="1" applyAlignment="1" applyProtection="1">
          *     <x:alignment horizontal="general" vertical="bottom" textRotation="0" wrapText="0" indent="0" relativeIndent="0" justifyLastLine="0" shrinkToFit="0" readingOrder="0" />
          *     <x:protection locked="1" hidden="0" />
          * </x:xf>
          */
         await NewWriter.WriteStartElementAsync(OldReader.Prefix, "xf", OldReader.NamespaceURI).ConfigureAwait(false);
-        await NewWriter.WriteAttributeStringAsync(null, "numFmtId", null, "21").ConfigureAwait(false);
+        await NewWriter.WriteAttributeStringAsync(null, "numFmtId", null, "46").ConfigureAwait(false);
         await NewWriter.WriteAttributeStringAsync(null, "fontId", null, $"{Context.OldElementInfos.FontCount}").ConfigureAwait(false);
         await NewWriter.WriteAttributeStringAsync(null, "fillId", null, $"{Context.OldElementInfos.FillCount}").ConfigureAwait(false);
         await NewWriter.WriteAttributeStringAsync(null, "borderId", null, $"{Context.OldElementInfos.BorderCount + 1}").ConfigureAwait(false);
diff --git a/src/MiniExcel.OpenXml/Styles/Builder/MinimalSheetStyleBuilder.cs b/src/MiniExcel.OpenXml/Styles/Builder/MinimalSheetStyleBuilder.cs
index 7afce315..68f58ca3 100644
--- a/src/MiniExcel.OpenXml/Styles/Builder/MinimalSheetStyleBuilder.cs
+++ b/src/MiniExcel.OpenXml/Styles/Builder/MinimalSheetStyleBuilder.cs
@@ -85,7 +85,7 @@ protected override async Task GenerateCellXfAsync()
          * <x:xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" />
          * <x:xf numFmtId="14" fontId="0" fillId="0" borderId="0" xfId="0" applyNumberFormat="1" />
          * <x:xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" />
-         * <x:xf numFmtId="21" fontId="0" fillId="0" borderId="0" xfId="0" applyNumberFormat="1" />
+         * <x:xf numFmtId="46" fontId="0" fillId="0" borderId="0" xfId="0" applyNumberFormat="1" />
          * */
 
         for (int i = 0; i < 3; i++)
@@ -115,7 +115,7 @@ protected override async Task GenerateCellXfAsync()
         await NewWriter.WriteAttributeStringAsync(null, "xfId", null, "0").ConfigureAwait(false);
         await NewWriter.WriteEndElementAsync().ConfigureAwait(false);
         await NewWriter.WriteStartElementAsync(OldReader.Prefix, "xf", OldReader.NamespaceURI).ConfigureAwait(false);
-        await NewWriter.WriteAttributeStringAsync(null, "numFmtId", null, "21").ConfigureAwait(false);
+        await NewWriter.WriteAttributeStringAsync(null, "numFmtId", null, "46").ConfigureAwait(false);
         await NewWriter.WriteAttributeStringAsync(null, "applyNumberFormat", null, "1").ConfigureAwait(false);
         await NewWriter.WriteEndElementAsync().ConfigureAwait(false);
 
diff --git a/src/MiniExcel.OpenXml/Writer/OpenXmlWriter.XmlGeneration.cs b/src/MiniExcel.OpenXml/Writer/OpenXmlWriter.XmlGeneration.cs
index 29e3aa00..5ba35110 100644
--- a/src/MiniExcel.OpenXml/Writer/OpenXmlWriter.XmlGeneration.cs
+++ b/src/MiniExcel.OpenXml/Writer/OpenXmlWriter.XmlGeneration.cs
@@ -11,8 +11,6 @@ internal partial class OpenXmlWriter
     private const string FillCellStyleIndex = "4";
     private const string TimeCellStyleIndex = "5";
     
-    private static readonly DateTime ExcelZeroDate = new(1899, 12, 31);
-    
     private readonly Dictionary<string, string> _zipContentsMap = [];
     private readonly Dictionary<string, int> _sharedStrings = [];
     
@@ -357,9 +355,6 @@ private static double CorrectDateTimeValue(DateTime value)
 
     private (string, string, string) GetTimeSpanValue(TimeSpan value, MiniExcelColumnMapping? columnMapping)
     {
-        if (value.TotalDays >= 1)
-            return GetDateTimeValue(ExcelZeroDate + value, columnMapping);
-
         var cellValue = value.TotalDays.ToString(CultureInfo.InvariantCulture);
         var format = columnMapping?.ExcelFormatId is { } fmt and not -1 ? fmt.ToString() : TimeCellStyleIndex;
 
diff --git a/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlExporterTests.cs b/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlExporterTests.cs
index ff693907..fdca47e6 100644
--- a/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlExporterTests.cs
+++ b/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlExporterTests.cs
@@ -17,6 +17,16 @@ static MiniExcelOpenXmlExporterTests()
         ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
     }
     
+    [Fact]
+    public void TimeSpanOfADayOrMoreStaysADuration()
+    {
+        using var path = AutoDeletingPath.Create();
+        _excelExporter.Export(path.ToString(), new[] { new { Duration = TimeSpan.FromHours(36.25) } });
+
+        var row = _excelImporter.Query(path.ToString(), true).First();
+        Assert.Equal(TimeSpan.FromHours(36.25), (TimeSpan)row.Duration);
+    }
+
     [Fact]
     public void SaveAsControlChracter()
     {