diff --git a/glm/gtc/round.inl b/glm/gtc/round.inl
index 255dec66..94fdd54b 100644
--- a/glm/gtc/round.inl
+++ b/glm/gtc/round.inl
@@ -104,10 +104,7 @@ namespace detail
 		GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
 		{
 			if(Source > genType(0))
-			{
-				genType Tmp = Source - genType(1);
-				return Tmp + (Multiple - std::fmod(Tmp, Multiple));
-			}
+				return Source + (Multiple - std::fmod(Source, Multiple));
 			else
 				return Source + std::fmod(-Source, Multiple);
 		}
@@ -152,10 +149,7 @@ namespace detail
 			if(Source >= genType(0))
 				return Source - std::fmod(Source, Multiple);
 			else
-			{
-				genType Tmp = Source + genType(1);
-				return Tmp - std::fmod(Tmp, Multiple) - Multiple;
-			}
+				return Source - std::fmod(Source, Multiple) - Multiple;
 		}
 	};
 
diff --git a/test/gtc/gtc_round.cpp b/test/gtc/gtc_round.cpp
index 1162d00f..aa6cf1a1 100644
--- a/test/gtc/gtc_round.cpp
+++ b/test/gtc/gtc_round.cpp
@@ -31,6 +31,7 @@
 #include <glm/gtc/round.hpp>
 #include <glm/gtc/type_precision.hpp>
 #include <glm/gtc/vec1.hpp>
+#include <glm/gtc/epsilon.hpp>
 #include <vector>
 #include <ctime>
 #include <cstdio>
@@ -293,6 +294,86 @@ namespace ceilPowerOfTwo
 	}
 }//namespace ceilPowerOfTwo
 
+namespace floorMultiple
+{
+	template <typename genType>
+	struct type
+	{
+		genType		Source;
+		genType		Multiple;
+		genType		Return;
+		genType		Epsilon;
+	};
+
+	int test_float()
+	{
+		type<glm::float64> const Data[] = 
+		{
+			{3.4, 0.3, 3.3, 0.0001},
+			{-1.4, 0.3, -1.5, 0.0001},
+		};
+
+		int Error(0);
+		
+		for(std::size_t i = 0, n = sizeof(Data) / sizeof(type<glm::float64>); i < n; ++i)
+		{
+			glm::float64 Result = glm::floorMultiple(Data[i].Source, Data[i].Multiple);
+			Error += glm::epsilonEqual(Data[i].Return, Result, Data[i].Epsilon) ? 0 : 1;
+		}
+
+		return Error;
+	}
+
+	int test()
+	{
+		int Error(0);
+
+		Error += test_float();
+
+		return Error;
+	}
+}//namespace floorMultiple
+
+namespace ceilMultiple
+{
+	template <typename genType>
+	struct type
+	{
+		genType		Source;
+		genType		Multiple;
+		genType		Return;
+		genType		Epsilon;
+	};
+
+	int test_float()
+	{
+		type<glm::float64> const Data[] = 
+		{
+			{3.4, 0.3, 3.6, 0.0001},
+			{-1.4, 0.3, -1.2, 0.0001},
+		};
+
+		int Error(0);
+		
+		for(std::size_t i = 0, n = sizeof(Data) / sizeof(type<glm::float64>); i < n; ++i)
+		{
+			glm::float64 Result = glm::ceilMultiple(Data[i].Source, Data[i].Multiple);
+			Error += glm::epsilonEqual(Data[i].Return, Result, Data[i].Epsilon) ? 0 : 1;
+		}
+
+		return Error;
+	}
+
+	int test()
+	{
+		int Error(0);
+
+		Error += test_float();
+
+		return Error;
+	}
+}//namespace ceilMultiple
+
 int main()
 {
 	int Error(0);
@@ -304,5 +385,8 @@ int main()
 		Error += ceilPowerOfTwo::perf();
 #	endif//NDEBUG
 
+	Error += floorMultiple::test();
+	Error += ceilMultiple::test();
+
 	return Error;
 }