diff --git a/poi-ooxml/src/test/java/org/apache/poi/ss/tests/format/TestCellFormatPart.java b/poi-ooxml/src/test/java/org/apache/poi/ss/tests/format/TestCellFormatPart.java
index 101fa6c10e..18254af451 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/ss/tests/format/TestCellFormatPart.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/ss/tests/format/TestCellFormatPart.java
@@ -29,6 +29,7 @@ import java.util.regex.Pattern;
 
 import javax.swing.JLabel;
 
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.ITestDataProvider;
 import org.apache.poi.ss.format.CellFormat;
 import org.apache.poi.ss.format.CellFormatPart;
@@ -217,4 +218,22 @@ class TestCellFormatPart {
             }
         }
     }
+
+    @Test
+    void testDecimalFormat() throws Exception {
+        // Create a workbook, row and cell to test with
+        try (Workbook wb = new HSSFWorkbook()) {
+            Sheet sheet = wb.createSheet();
+            Row row = sheet.createRow(0);
+            Cell cell = row.createCell(0);
+
+            CellFormat cf = CellFormat.getInstance("[<=.01]0.00%;#,##0");
+
+            cell.setCellValue(1);
+            assertEquals("1", cf.apply(cell).text);
+
+            cell.setCellValue(.001);
+            assertEquals("0.10%", cf.apply(cell).text);
+        }
+    }
 }
diff --git a/poi/src/main/java/org/apache/poi/ss/format/CellFormatPart.java b/poi/src/main/java/org/apache/poi/ss/format/CellFormatPart.java
index c505314ae0..b86e7aba55 100644
--- a/poi/src/main/java/org/apache/poi/ss/format/CellFormatPart.java
+++ b/poi/src/main/java/org/apache/poi/ss/format/CellFormatPart.java
@@ -104,7 +104,7 @@ public class CellFormatPart {
     static {
         // A condition specification
         String condition = "([<>=]=?|!=|<>)    # The operator\n" +
-                "  \\s*(-?[0-9]+(?:\\.[0-9]*)?)\\s*  # The constant to test against\n";
+                "  \\s*(-?([0-9]+(?:\\.[0-9]*)?)|(\\.[0-9]*))\\s*  # The constant to test against\n";;
 
         // A currency symbol / string, in a specific locale
         String currency = "(\\[\\$.{0,3}(-[0-9a-f]{3,4})?\\])";