diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/DoublePropertyValidator.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/DoublePropertyValidator.java
index d3b6966..337c7ed 100644
--- a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/DoublePropertyValidator.java
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/DoublePropertyValidator.java
@@ -48,7 +48,7 @@ public class DoublePropertyValidator<T>
      */
     public final DoublePropertyValidator<T> gt(final double min) {
         return withRule(Conditions.greaterThan(min),
-                "The input must be greater than '%s'.", min);
+                "The input must be greater than '%f'.", min);
     }
 
     /**
@@ -105,7 +105,7 @@ public class DoublePropertyValidator<T>
      */
     public final DoublePropertyValidator<T> ge(final double min) {
         return withRule(Conditions.greaterThanOrEqualTo(min),
-                "The input must be greater than or equal to '%s'.", min);
+                "The input must be greater than or equal to '%f'.", min);
     }
 
     /**
@@ -162,7 +162,7 @@ public class DoublePropertyValidator<T>
      */
     public final DoublePropertyValidator<T> lt(final double max) {
         return withRule(Conditions.lessThan(max),
-                "The input must be less than '%s'.", max);
+                "The input must be less than '%f'.", max);
     }
 
     /**
@@ -219,7 +219,7 @@ public class DoublePropertyValidator<T>
      */
     public final DoublePropertyValidator<T> le(final double max) {
         return withRule(Conditions.lessThanOrEqualTo(max),
-                "The input must be less than or equal to '%s'.", max);
+                "The input must be less than or equal to '%f'.", max);
     }
 
     /**
diff --git a/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/DoublePropertyValidatorTests.java b/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/DoublePropertyValidatorTests.java
index 0d4c426..7c4ee43 100644
--- a/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/DoublePropertyValidatorTests.java
+++ b/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/DoublePropertyValidatorTests.java
@@ -87,7 +87,7 @@ public class DoublePropertyValidatorTests {
 
         ValidationException e = assertThrows(
                 ValidationException.class, () -> validator.validate(command));
-        assertEquals(String.format("The input must be greater than '%s'.", MIN), e.getMessage());
+        assertEquals(String.format("The input must be greater than '%f'.", MIN), e.getMessage());
     }
 
     @ParameterizedTest
@@ -196,7 +196,7 @@ public class DoublePropertyValidatorTests {
 
         ValidationException e = assertThrows(
                 ValidationException.class, () -> validator.validate(command));
-        assertEquals(String.format("The input must be greater than or equal to '%s'.", MIN), e.getMessage());
+        assertEquals(String.format("The input must be greater than or equal to '%f'.", MIN), e.getMessage());
     }
 
     @ParameterizedTest
@@ -305,7 +305,7 @@ public class DoublePropertyValidatorTests {
 
         ValidationException e = assertThrows(
                 ValidationException.class, () -> validator.validate(command));
-        assertEquals(String.format("The input must be less than '%s'.", MAX), e.getMessage());
+        assertEquals(String.format("The input must be less than '%f'.", MAX), e.getMessage());
     }
 
     @ParameterizedTest
@@ -414,7 +414,7 @@ public class DoublePropertyValidatorTests {
 
         ValidationException e = assertThrows(
                 ValidationException.class, () -> validator.validate(command));
-        assertEquals(String.format("The input must be less than or equal to '%s'.", MAX), e.getMessage());
+        assertEquals(String.format("The input must be less than or equal to '%f'.", MAX), e.getMessage());
     }
 
     @ParameterizedTest