diff --git a/packages/core/src/lib/connection_manager/shard_reader.spec.ts b/packages/core/src/lib/connection_manager/shard_reader.spec.ts
index 7f38c83190..8abb90265b 100644
--- a/packages/core/src/lib/connection_manager/shard_reader.spec.ts
+++ b/packages/core/src/lib/connection_manager/shard_reader.spec.ts
@@ -29,7 +29,10 @@ describe("ShardReader", function () {
 
   const testContentTopic = "/test/1/waku-light-push/utf8";
   const testClusterId = 3;
-  const testShardIndex = contentTopicToShardIndex(testContentTopic);
+  const testShardIndex = contentTopicToShardIndex(
+    testContentTopic,
+    DEFAULT_NUM_SHARDS
+  );
 
   const testNetworkConfig: AutoSharding = {
     clusterId: testClusterId,
diff --git a/packages/tests/tests/filter/utils.ts b/packages/tests/tests/filter/utils.ts
index a679f5337a..111ad5f420 100644
--- a/packages/tests/tests/filter/utils.ts
+++ b/packages/tests/tests/filter/utils.ts
@@ -10,10 +10,14 @@ import { utf8ToBytes } from "@waku/utils/bytes";
 export const log = new Logger("test:filter");
 export const TestContentTopic = "/test/1/waku-filter/default";
 export const TestClusterId = 2;
-export const TestShardIndex = contentTopicToShardIndex(TestContentTopic);
+export const TestNumShardsInCluster = 8;
+export const TestShardIndex = contentTopicToShardIndex(
+  TestContentTopic,
+  TestNumShardsInCluster
+);
 export const TestNetworkConfig = {
   clusterId: TestClusterId,
-  numShardsInCluster: 8
+  numShardsInCluster: TestNumShardsInCluster
 };
 export const TestRoutingInfo = createRoutingInfo(TestNetworkConfig, {
   contentTopic: TestContentTopic
diff --git a/packages/tests/tests/sharding/peer_management.spec.ts b/packages/tests/tests/sharding/peer_management.spec.ts
index c0dec2e1fd..6d734828c9 100644
--- a/packages/tests/tests/sharding/peer_management.spec.ts
+++ b/packages/tests/tests/sharding/peer_management.spec.ts
@@ -200,7 +200,8 @@ describe("Static Sharding: Peer Management", function () {
 describe("Autosharding: Peer Management", function () {
   const ContentTopic = "/myapp/1/latest/proto";
   const clusterId = 8;
-  const Shard = [contentTopicToShardIndex(ContentTopic)];
+  const numShardsInCluster = 8;
+  const Shard = [contentTopicToShardIndex(ContentTopic, numShardsInCluster)];
 
   describe("Peer Exchange", function () {
     let waku: LightNode;
diff --git a/packages/utils/src/common/sharding/index.spec.ts b/packages/utils/src/common/sharding/index.spec.ts
index 7e5056dbe5..28b5aeba2e 100644
--- a/packages/utils/src/common/sharding/index.spec.ts
+++ b/packages/utils/src/common/sharding/index.spec.ts
@@ -9,6 +9,9 @@ import {
   pubsubTopicToSingleShardInfo
 } from "./index.js";
 
+const ClusterId = 0;
+const NumShardsInCluster = 8;
+
 const testInvalidCases = (
   contentTopics: string[],
   expectedError: string
@@ -112,7 +115,9 @@ describe("contentTopicToShardIndex", () => {
   ];
   contentTopicsWithExpectedShards.forEach(([topic, expectedShard]) => {
     it(`should correctly map ${topic} to shard index ${expectedShard}`, () => {
-      expect(contentTopicToShardIndex(topic)).to.eq(expectedShard);
+      expect(contentTopicToShardIndex(topic, NumShardsInCluster)).to.eq(
+        expectedShard
+      );
     });
   });
 
@@ -137,8 +142,8 @@ describe("contentTopicToShardIndex", () => {
       ["/waku/2/content/test.js", "/waku/2/users/proto"]
     ];
     for (const [topic1, topic2] of contentTopics) {
-      expect(contentTopicToShardIndex(topic1)).to.eq(
-        contentTopicToShardIndex(topic2)
+      expect(contentTopicToShardIndex(topic1, NumShardsInCluster)).to.eq(
+        contentTopicToShardIndex(topic2, NumShardsInCluster)
       );
     }
   });
@@ -147,9 +152,15 @@ describe("contentTopicToShardIndex", () => {
 describe("contentTopicsByPubsubTopic", () => {
   it("groups content topics by expected pubsub topic", () => {
     const contentTopics = ["/toychat/2/huilong/proto", "/myapp/1/latest/proto"];
-    const grouped = contentTopicsByPubsubTopic(contentTopics);
+    const grouped = contentTopicsByPubsubTopic(
+      contentTopics,
+      ClusterId,
+      NumShardsInCluster
+    );
+
     for (const contentTopic of contentTopics) {
       const pubsubTopic = contentTopicToPubsubTopic(contentTopic, 0, 8);
+
       expect(grouped.get(pubsubTopic)?.includes(contentTopic)).to.be.true;
     }
   });
@@ -159,7 +170,11 @@ describe("contentTopicsByPubsubTopic", () => {
       "/app/22/sometopic/someencoding",
       "/app/22/anothertopic/otherencoding"
     ];
-    const grouped = contentTopicsByPubsubTopic(contentTopics);
+    const grouped = contentTopicsByPubsubTopic(
+      contentTopics,
+      ClusterId,
+      NumShardsInCluster
+    );
     expect(grouped.size).to.eq(1); // Only one pubsub topic expected
     const pubsubTopic = contentTopicToPubsubTopic(contentTopics[0], 0, 8);
     expect(grouped.get(pubsubTopic)?.length).to.eq(2); // Both topics should be grouped under the same pubsub topic
@@ -169,8 +184,16 @@ describe("contentTopicsByPubsubTopic", () => {
     const contentTopics = ["/app/22/sometopic/someencoding"];
     const clusterId1 = 3;
     const clusterId2 = 2;
-    const grouped1 = contentTopicsByPubsubTopic(contentTopics, clusterId1);
-    const grouped2 = contentTopicsByPubsubTopic(contentTopics, clusterId2);
+    const grouped1 = contentTopicsByPubsubTopic(
+      contentTopics,
+      clusterId1,
+      NumShardsInCluster
+    );
+    const grouped2 = contentTopicsByPubsubTopic(
+      contentTopics,
+      clusterId2,
+      NumShardsInCluster
+    );
     const pubsubTopic1 = contentTopicToPubsubTopic(
       contentTopics[0],
       clusterId1,
@@ -221,7 +244,13 @@ describe("contentTopicsByPubsubTopic", () => {
 
   it("throws an error for improperly formatted content topics", () => {
     const invalidContentTopics = ["/invalid/format"];
-    expect(() => contentTopicsByPubsubTopic(invalidContentTopics)).to.throw();
+    expect(() =>
+      contentTopicsByPubsubTopic(
+        invalidContentTopics,
+        ClusterId,
+        NumShardsInCluster
+      )
+    ).to.throw();
   });
 });
 
diff --git a/packages/utils/src/common/sharding/index.ts b/packages/utils/src/common/sharding/index.ts
index e48522ac22..495ea42c6e 100644
--- a/packages/utils/src/common/sharding/index.ts
+++ b/packages/utils/src/common/sharding/index.ts
@@ -2,7 +2,6 @@ import { sha256 } from "@noble/hashes/sha256";
 import {
   type ClusterId,
   ContentTopic,
-  DEFAULT_CLUSTER_ID,
   PubsubTopic,
   type ShardId
 } from "@waku/interfaces";
@@ -116,7 +115,7 @@ export function ensureValidContentTopic(
  */
 export function contentTopicToShardIndex(
   contentTopic: ContentTopic,
-  numShardsInCluster: number = 8
+  numShardsInCluster: number
 ): number {
   const { application, version } = ensureValidContentTopic(contentTopic);
   const digest = sha256(
@@ -145,8 +144,8 @@ export function contentTopicToPubsubTopic(
  */
 export function contentTopicsByPubsubTopic(
   contentTopics: ContentTopic[],
-  clusterId: number = DEFAULT_CLUSTER_ID,
-  networkShards: number = 8
+  clusterId: number,
+  networkShards: number
 ): Map<string, Array<string>> {
   const groupedContentTopics = new Map();
   for (const contentTopic of contentTopics) {