diff --git a/src/utils.typ b/src/utils.typ
index b4eae86..219501c 100644
--- a/src/utils.typ
+++ b/src/utils.typ
@@ -51,7 +51,10 @@
   let w = m.width
   let h = m.height
   let r = if w == 0pt {0} else {
-    if width == auto {1} else {
+    if width == auto {1}
+    else if type(width) == length {
+      width / w
+    } else {
       size.width * width / w
     }
   }