diff --git a/src/awst_build/eb/storage/box/box-ref.ts b/src/awst_build/eb/storage/box/box-ref.ts
index 84d0a009..6e952afa 100644
--- a/src/awst_build/eb/storage/box/box-ref.ts
+++ b/src/awst_build/eb/storage/box/box-ref.ts
@@ -56,7 +56,7 @@ export class BoxRefExpressionBuilder extends BoxProxyExpressionBuilder<BoxRefPTy
       case 'exists':
       case 'length': {
         const boxLength = nodeFactory.intrinsicCall({
-          opCode: 'box_length',
+          opCode: 'box_len',
           stackArgs: [boxValueExpr],
           wtype: new WTuple({ types: [uint64WType, boolWType], immutable: true }),
           immediates: [],
diff --git a/src/awst_build/eb/storage/box/box.ts b/src/awst_build/eb/storage/box/box.ts
index e929e5f7..232319a5 100644
--- a/src/awst_build/eb/storage/box/box.ts
+++ b/src/awst_build/eb/storage/box/box.ts
@@ -59,7 +59,7 @@ export class BoxExpressionBuilder extends BoxProxyExpressionBuilder<BoxPType> {
         return instanceEb(
           nodeFactory.checkedMaybe({
             expr: nodeFactory.intrinsicCall({
-              opCode: 'box_length',
+              opCode: 'box_len',
               stackArgs: [boxValueExpr],
               wtype: new WTuple({ types: [uint64WType, boolWType], immutable: true }),
               immediates: [],