diff --git a/packages/mermaid/src/diagrams/block/layout.ts b/packages/mermaid/src/diagrams/block/layout.ts
index 7f44a5f19f..53e60a6977 100644
--- a/packages/mermaid/src/diagrams/block/layout.ts
+++ b/packages/mermaid/src/diagrams/block/layout.ts
@@ -61,7 +61,7 @@ const getMaxChildSize = (block: Block) => {
       continue;
     }
     if (width > maxWidth) {
-      maxWidth = width / (block.widthInColumns ?? 1);
+      maxWidth = width / (child.widthInColumns ?? 1);
     }
     if (height > maxHeight) {
       maxHeight = height;