diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1
index 15e6a0c55d..a1c7c19f8f 100644
--- a/DOCS/man/en/mplayer.1
+++ b/DOCS/man/en/mplayer.1
@@ -4431,9 +4431,9 @@ Expands to fit an aspect instead of a resolution (default: 0).
 .I EXAMPLE:
 .PD 0
 .RSs
-.IP expand=800::::3/4
+.IP expand=800::::4/3
 Expands to 800x600, unless the source is higher resolution, in which
-case it expands to fill a 3/4 aspect.
+case it expands to fill a 4/3 aspect.
 .RE
 .PD 1
 .IPs <r>\ \ 
diff --git a/libmpcodecs/vf_expand.c b/libmpcodecs/vf_expand.c
index 946f84fc19..ab7b71aff0 100644
--- a/libmpcodecs/vf_expand.c
+++ b/libmpcodecs/vf_expand.c
@@ -183,10 +183,10 @@ static int config(struct vf_instance_s* vf,
         else if( vf->priv->exp_h<height ) vf->priv->exp_h=height;
 #endif
     if (vf->priv->aspect) {
-        if (vf->priv->exp_h < vf->priv->exp_w * vf->priv->aspect) {
-            vf->priv->exp_h = vf->priv->exp_w * vf->priv->aspect;
+        if (vf->priv->exp_h < vf->priv->exp_w / vf->priv->aspect) {
+            vf->priv->exp_h = vf->priv->exp_w / vf->priv->aspect;
         } else {
-            vf->priv->exp_w = vf->priv->exp_h / vf->priv->aspect;
+            vf->priv->exp_w = vf->priv->exp_h * vf->priv->aspect;
         }
     }
     if (vf->priv->round > 1) { // round up.