diff --git a/batched_atomic.test.ts b/batched_atomic.test.ts
index 0e117a1..52dddc2 100644
--- a/batched_atomic.test.ts
+++ b/batched_atomic.test.ts
@@ -155,3 +155,22 @@ Deno.test({
     return teardown();
   },
 });
+
+Deno.test({
+  name: "batched atomic mutate handles many items",
+  async fn() {
+    const kv = await setup();
+    const items = Array
+      .from({ length: 1000 }, (_, index) => index)
+      .map((i) => ({
+        key: [i],
+        value: "x".repeat(2000),
+        type: "set" as const,
+      }));
+    const op = batchedAtomic(kv);
+    op.mutate(...items);
+    const actual = await op.commit();
+    assert(actual.every(({ ok }) => ok));
+    return teardown();
+  },
+});
diff --git a/batched_atomic.ts b/batched_atomic.ts
index 0a05f39..de1b028 100644
--- a/batched_atomic.ts
+++ b/batched_atomic.ts
@@ -142,7 +142,28 @@ export class BatchedAtomicOperation {
    * {@linkcode Deno.KvMutation}.
    */
   mutate(...mutations: Deno.KvMutation[]): this {
-    return this.#enqueue("mutate", mutations);
+    for (const mutation of mutations) {
+      switch (mutation.type) {
+        case "set":
+          this.set(mutation.key, mutation.value, {
+            expireIn: mutation.expireIn,
+          });
+          break;
+        case "delete":
+          this.delete(mutation.key);
+          break;
+        case "sum":
+          this.sum(mutation.key, mutation.value.value);
+          break;
+        case "max":
+          this.max(mutation.key, mutation.value.value);
+          break;
+        case "min":
+          this.min(mutation.key, mutation.value.value);
+          break;
+      }
+    }
+    return this;
   }
 
   /**
@@ -297,18 +318,7 @@ export class BatchedAtomicOperation {
           hasCheck = true;
         } else {
           mutations++;
-          if (method === "mutate") {
-            for (const mutation of args as Deno.KvMutation[]) {
-              const keyLen = estimateSize(mutation.key);
-              payloadBytes += keyLen;
-              keyBytes += keyLen;
-              if (mutation.type === "set") {
-                payloadBytes += estimateSize(mutation.value);
-              } else if (mutation.type !== "delete") {
-                payloadBytes += 8;
-              }
-            }
-          } else if (method === "max" || method === "min" || method === "sum") {
+          if (method === "max" || method === "min" || method === "sum") {
             const [key] = args as [Deno.KvKey];
             const keyLen = estimateSize(key);
             keyBytes += keyLen;