diff --git a/dlls/gdiplus/gdiplus.c b/dlls/gdiplus/gdiplus.c
index edbfb1cb2c6..9267b90d498 100644
--- a/dlls/gdiplus/gdiplus.c
+++ b/dlls/gdiplus/gdiplus.c
@@ -218,7 +218,7 @@ COLORREF ARGB2COLORREF(ARGB color)
 }
 
 /* Like atan2, but puts angle in correct quadrant if dx is 0. */
-FLOAT gdiplus_atan2(FLOAT dy, FLOAT dx)
+REAL gdiplus_atan2(REAL dy, REAL dx)
 {
     if((dx == 0.0) && (dy != 0.0))
         return dy > 0.0 ? M_PI_2 : -M_PI_2;
diff --git a/dlls/gdiplus/gdiplus_private.h b/dlls/gdiplus/gdiplus_private.h
index 3ce92a16163..ee120d95cc7 100644
--- a/dlls/gdiplus/gdiplus_private.h
+++ b/dlls/gdiplus/gdiplus_private.h
@@ -40,7 +40,7 @@
 COLORREF ARGB2COLORREF(ARGB color);
 extern INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
     REAL startAngle, REAL sweepAngle);
-extern FLOAT gdiplus_atan2(FLOAT dy, FLOAT dx);
+extern REAL gdiplus_atan2(REAL dy, REAL dx);
 
 static inline INT roundr(REAL x)
 {
diff --git a/dlls/gdiplus/pen.c b/dlls/gdiplus/pen.c
index 388567a9485..20a44bc9529 100644
--- a/dlls/gdiplus/pen.c
+++ b/dlls/gdiplus/pen.c
@@ -84,7 +84,7 @@ GpStatus WINGDIPAPI GdipClonePen(GpPen *pen, GpPen **clonepen)
     return Ok;
 }
 
-GpStatus WINGDIPAPI GdipCreatePen1(ARGB color, FLOAT width, GpUnit unit,
+GpStatus WINGDIPAPI GdipCreatePen1(ARGB color, REAL width, GpUnit unit,
     GpPen **pen)
 {
     GpPen *gp_pen;