diff --git a/packages/block-editor/src/components/block-canvas/style.scss b/packages/block-editor/src/components/block-canvas/style.scss
index 525c79be53504b..43176723195445 100644
--- a/packages/block-editor/src/components/block-canvas/style.scss
+++ b/packages/block-editor/src/components/block-canvas/style.scss
@@ -3,4 +3,5 @@ iframe[name="editor-canvas"] {
 	height: 100%;
 	display: block;
 	background-color: $gray-300;
+	box-sizing: border-box;
 }