diff --git a/src/web/vaev-layout/box.h b/src/web/vaev-layout/box.h
index fc76b982b5..d49c2c7bed 100644
--- a/src/web/vaev-layout/box.h
+++ b/src/web/vaev-layout/box.h
@@ -23,6 +23,10 @@ struct Box {
     RectPx contentBox() const {
         return paddings.shrink(Math::Flow::LEFT_TO_RIGHT, paddingBox());
     }
+
+    RectPx marginBox() const {
+        return margins.grow(Math::Flow::LEFT_TO_RIGHT, borderBox);
+    }
 };
 
 } // namespace Vaev::Layout