diff --git a/components/fpspreadsheet/source/common/fpsopendocument.pas b/components/fpspreadsheet/source/common/fpsopendocument.pas
index 949a91fd3..893af8f56 100644
--- a/components/fpspreadsheet/source/common/fpsopendocument.pas
+++ b/components/fpspreadsheet/source/common/fpsopendocument.pas
@@ -454,13 +454,22 @@ const
     '5Rating', '5Quarters', '5Boxes'      // is5Rating, is5Quarters, is5Boxes
   );
 
-function CFOperandToStr(v: variant; AWorksheet: TsWorksheet): String;
+function CFOperandToStr(v: variant; AWorksheet: TsWorksheet;
+  const AFormatSettings: TFormatSettings): String;
 var
   r,c: Cardinal;
+  f: Double;
 begin
-  Result := VarToStr(v);
-  if Result = '' then
-    exit;
+  if VarIsFloat(v) then
+  begin
+    f := v;
+    Result := Format('%g', [f], AFormatSettings);
+  end else
+  begin
+    Result := VarToStr(v);
+    if Result = '' then
+      exit;
+  end;
 
   if VarIsStr(v) then begin
     // Special case: v is a formula, i.e. begins with '='
@@ -6592,8 +6601,8 @@ begin
       begin
         cf_cellRule := TsCFCellRule(cf.Rules[j]);
         cf_styleName := Format('conditional_%d', [cf_CellRule.FormatIndex]);
-        value1Str := CFOperandToStr(cf_cellRule.Operand1, sheet);
-        value2Str := CFOperandToStr(cf_cellRule.Operand2, sheet);
+        value1Str := CFOperandToStr(cf_cellRule.Operand1, sheet, FPointSeparatorSettings);
+        value2Str := CFOperandToStr(cf_cellRule.Operand2, sheet, FPointSeparatorSettings);
         opStr := Format(CF_CALCEXT_OP[cf_cellRule.Condition], [value1Str, value2str]);
         isDateFmt := cf_cellRule.Condition in [cfcYesterday..cfcNextYear];
         if opStr <> '' then
@@ -8123,12 +8132,12 @@ begin
         operand1Str := VarToStr(cf_cellRule.Operand1);
         if (operand1Str <> '') and (operand1Str[1] <> '=') then
           operand1Str := '=' + operand1Str;
-        operand1Str := CFOperandToStr(operand1Str, cf_sheet);
+        operand1Str := CFOperandToStr(operand1Str, cf_sheet, FPointSeparatorSettings);
         operand2Str := '';
       end else
       begin
-        operand1Str := CFOperandToStr(cf_cellrule.Operand1, cf_sheet);
-        operand2Str := CFOperandToStr(cf_cellrule.Operand2, cf_sheet);
+        operand1Str := CFOperandToStr(cf_cellrule.Operand1, cf_sheet, FPointSeparatorSettings);
+        operand2Str := CFOperandToStr(cf_cellrule.Operand2, cf_sheet, FPointSeparatorSettings);
       end;
       cf_condition := Format(CF_STYLE_OP[cf_cellRule.Condition], [operand1Str, operand2Str]);
 
diff --git a/components/fpspreadsheet/source/common/xlsxooxml.pas b/components/fpspreadsheet/source/common/xlsxooxml.pas
index 4133e32cd..4cbea5df6 100644
--- a/components/fpspreadsheet/source/common/xlsxooxml.pas
+++ b/components/fpspreadsheet/source/common/xlsxooxml.pas
@@ -548,15 +548,23 @@ begin
   end;
 end;
 
-function CFOperandToStr(v: Variant): String;
+function CFOperandToStr(v: Variant; const AFormatSettings: TFormatSettings): String;
 const
   ERR = cardinal(-1);
 var
   r, c: Cardinal;
+  f: Double;
 begin
-  Result := VarToStr(v);
-  if Result = '' then
-    exit;
+  if VarIsFloat(v) then
+  begin
+    f := v;
+    Result := Format('%g', [f], AFormatSettings);
+  end else
+  begin
+    Result := VarToStr(v);
+    if Result = '' then
+      exit;
+  end;
 
   if Result[1] = '=' then
     Delete(Result, 1, 1)
@@ -4219,11 +4227,11 @@ begin
   case ARule.Condition of
     cfcEqual..cfcNotBetween:
       begin
-        s := CFOperandToStr(ARule.Operand1);
+        s := CFOperandToStr(ARule.Operand1, FPointSeparatorSettings);
         formula1Str := Format('<formula>%s</formula>', [s]);
         if (ARule.Condition in [cfcBetween, cfcNotBetween]) then
         begin
-          s := CFOperandToStr(ARule.Operand2);
+          s := CFOperandToStr(ARule.Operand2, FPointSeparatorSettings);
           formula2Str := Format('<formula>%s</formula>', [s]);
         end;
       end;
@@ -4234,7 +4242,7 @@ begin
         if (ARule.Condition in [cfcAboveEqualAverage, cfcBelowEqualAverage]) then
           param2Str := ' equalAverage="1"';
         if VarIsNumeric(ARule.Operand1) or (ARule.Operand1 = 0) then
-          param3Str := Format(' stdDev="%g"', [double(ARule.Operand1)]);
+          param3Str := Format(' stdDev="%g"', [double(ARule.Operand1)], FPointSeparatorSettings);
       end;
     cfcTop, cfcBottom, cfcTopPercent, cfcBottomPercent:
       begin