diff --git a/addon/src/utils/css-calculation.ts b/addon/src/utils/css-calculation.ts
index eab8e19b..a31a7946 100644
--- a/addon/src/utils/css-calculation.ts
+++ b/addon/src/utils/css-calculation.ts
@@ -8,7 +8,9 @@
 */
 export function getBorderSpacing(el: Element) {
   const css = getComputedStyle(el).borderSpacing; // '0px 0px'
-  const [horizontal, vertical] = css.split(' ');
+
+  const [horizontal, initialVertical] = css.split(' ');
+  const vertical = initialVertical === undefined ? horizontal : initialVertical;
 
   return {
     horizontal: parseFloat(horizontal ?? ''),