diff --git a/mem/mem_linux.go b/mem/mem_linux.go
index fc9226219d7fb4398d53797b4e5bc7ad63296b12..899da83dffb4c2fa7e17ebad997846300f1d020b 100644
--- a/mem/mem_linux.go
+++ b/mem/mem_linux.go
@@ -51,7 +51,7 @@ func VirtualMemory() (*VirtualMemoryStat, error) {
 	if !memavail {
 		ret.Available = ret.Free + ret.Buffers + ret.Cached
 	}
-	ret.Used = ret.Total - ret.Free
+	ret.Used = ret.Total - ret.Available
 	ret.UsedPercent = float64(ret.Total-ret.Available) / float64(ret.Total) * 100.0
 
 	return ret, nil