diff --git a/src/os/darwin/darwin_sigar.c b/src/os/darwin/darwin_sigar.c
index b32e726b..1007ffb2 100644
--- a/src/os/darwin/darwin_sigar.c
+++ b/src/os/darwin/darwin_sigar.c
@@ -460,7 +460,8 @@ int sigar_mem_get(sigar_t *sigar, sigar_mem_t *mem)
         return status;
     }
 
-    mem->free = vmstat.free_count * sigar->pagesize;
+    mem->free = vmstat.free_count;
+    mem->free *= sigar->pagesize;
 #elif defined(__FreeBSD__)
     if ((status = sigar_vmstat(sigar, &vmstat)) == SIGAR_OK) {
         mem->free = vmstat.v_free_count;