diff --git a/src/js/test/test-stats.js b/src/js/test/test-stats.js
index 72f10d510..cb33ed2bb 100644
--- a/src/js/test/test-stats.js
+++ b/src/js/test/test-stats.js
@@ -254,7 +254,8 @@ export function pushBurstToHistory(speed) {
 }
 
 export function calculateAccuracy() {
-  return (accuracy.correct / (accuracy.correct + accuracy.incorrect)) * 100;
+  let acc = (accuracy.correct / (accuracy.correct + accuracy.incorrect)) * 100;
+  return isNaN(acc) ? 100 : acc;
 }
 
 export function incrementAccuracy(correctincorrect) {