diff --git a/src/app/(features)/memorize/interval-preview.ts b/src/app/(features)/memorize/interval-preview.ts
index a892ac7..a09f574 100644
--- a/src/app/(features)/memorize/interval-preview.ts
+++ b/src/app/(features)/memorize/interval-preview.ts
@@ -36,24 +36,24 @@ function calculateNewCardIntervals(): PreviewIntervals {
   };
 }
 
-function calculateLearningIntervals(left: number): PreviewIntervals {
-  const steps = SM2_CONFIG.LEARNING_STEPS;
+function calculateLearningIntervals(left: number, isRelearning: boolean): PreviewIntervals {
+  const steps = isRelearning ? SM2_CONFIG.RELEARNING_STEPS : SM2_CONFIG.LEARNING_STEPS;
   const stepIndex = Math.floor(left % 1000);
   
-  const again = steps[0];
+  const again = steps[0] ?? 1;
   
   let hard: number;
   if (stepIndex === 0 && steps.length >= 2) {
-    hard = (steps[0] + steps[1]) / 2;
-  } else if (stepIndex < steps.length - 1) {
-    hard = steps[stepIndex];
+    const step0 = steps[0] ?? 1;
+    const step1 = steps[1] ?? step0;
+    hard = (step0 + step1) / 2;
   } else {
-    hard = SM2_CONFIG.GRADUATING_INTERVAL_GOOD * 1440;
+    hard = steps[stepIndex] ?? steps[0] ?? 1;
   }
   
   let good: number;
   if (stepIndex < steps.length - 1) {
-    good = steps[stepIndex + 1];
+    good = steps[stepIndex + 1] ?? steps[0] ?? 1;
   } else {
     good = SM2_CONFIG.GRADUATING_INTERVAL_GOOD * 1440;
   }
@@ -68,8 +68,9 @@ export function calculatePreviewIntervals(card: CardPreview): PreviewIntervals {
     case CardType.NEW:
       return calculateNewCardIntervals();
     case CardType.LEARNING:
+      return calculateLearningIntervals(card.left, false);
     case CardType.RELEARNING:
-      return calculateLearningIntervals(card.left);
+      return calculateLearningIntervals(card.left, true);
     case CardType.REVIEW:
     default:
       return calculateReviewIntervals(card.ivl, card.factor);