diff --git a/mem/mem_windows.go b/mem/mem_windows.go
index 015c1a1..ba6497a 100644
--- a/mem/mem_windows.go
+++ b/mem/mem_windows.go
@@ -49,7 +49,7 @@ func VirtualMemoryWithContext(_ context.Context) (*VirtualMemoryStat, error) {
 		Total:       memInfo.ullTotalPhys,
 		Available:   memInfo.ullAvailPhys,
 		Free:        memInfo.ullAvailPhys,
-		UsedPercent: float64(memInfo.dwMemoryLoad),
+		UsedPercent: float64(memInfo.ullTotalPhys-memInfo.ullAvailPhys) / float64(memInfo.ullTotalPhys) * 100,
 	}
 
 	ret.Used = ret.Total - ret.Available