diff --git a/src/g_shared/sbarinfo_commands.cpp b/src/g_shared/sbarinfo_commands.cpp
index 47785076e..b7827f6bd 100644
--- a/src/g_shared/sbarinfo_commands.cpp
+++ b/src/g_shared/sbarinfo_commands.cpp
@@ -1949,10 +1949,10 @@ class CommandAspectRatio : public SBarInfoCommandFlowControl
 			};
 
 			int ratio = ratioTypes[0].second;
-			float distance = abs(ratioTypes[0].first - aspect);
+			float distance = fabs(ratioTypes[0].first - aspect);
 			for (int i = 1; ratioTypes[i].first != 0.0f; i++)
 			{
-				float d = abs(ratioTypes[i].first - aspect);
+				float d = fabs(ratioTypes[i].first - aspect);
 				if (d < distance)
 				{
 					ratio = ratioTypes[i].second;
diff --git a/src/v_video.cpp b/src/v_video.cpp
index 43458dc63..20e1f526c 100644
--- a/src/v_video.cpp
+++ b/src/v_video.cpp
@@ -1681,10 +1681,10 @@ int CheckRatio (int width, int height, int *trueratio)
 	};
 
 	int ratio = ratioTypes[0].second;
-	float distance = abs(ratioTypes[0].first - aspect);
+	float distance = fabs(ratioTypes[0].first - aspect);
 	for (int i = 1; ratioTypes[i].first != 0.0f; i++)
 	{
-		float d = abs(ratioTypes[i].first - aspect);
+		float d = fabs(ratioTypes[i].first - aspect);
 		if (d < distance)
 		{
 			ratio = ratioTypes[i].second;