diff --git a/gap-card.js b/gap-card.js
index c6594bc..303e805 100644
--- a/gap-card.js
+++ b/gap-card.js
@@ -2,7 +2,7 @@ class GapCard extends HTMLElement {
 
   setConfig(config) {
     this.height = ('height' in config) ? config.height : 50;
-    this.size = ('size' in config) ? config.size :  Math.ceil(this.size/50);
+    this.size = ('size' in config) ? config.size :  Math.ceil(this.height/50);
     this.style.setProperty('height', this.height + 'px');
   }