diff --git a/src/PrintOne.ts b/src/PrintOne.ts
index f928c54..ea78677 100644
--- a/src/PrintOne.ts
+++ b/src/PrintOne.ts
@@ -436,7 +436,7 @@ export class PrintOne {
         templates?: InFilter<string | Template>;
         format?: InFilter;
         status?: InFilter<BatchStatus>;
-        isBillable?: InFilter;
+        isBillable?: boolean;
       };
     } = {},
   ): Promise<PaginatedResponse<Batch>> {
diff --git a/test/PrintOne.spec.ts b/test/PrintOne.spec.ts
index a631fd1..385d370 100644
--- a/test/PrintOne.spec.ts
+++ b/test/PrintOne.spec.ts
@@ -1562,6 +1562,28 @@ describe("getBatches", function () {
     expect(batch.billingId).toEqual("test");
   });
 
+  it("should apply the isBillable filter", async function () {
+    // arrange
+
+    // act
+    const batches = await client.getBatches({
+      limit: 1,
+      filter: {
+        isBillable: true,
+      },
+    });
+    const batch = batches.data[0];
+
+    if (batch === undefined) {
+      console.warn("No orders found, skipping test");
+      return;
+    }
+
+    // assert
+    expect(batch).toBeDefined();
+    expect(batch.isBillable).toEqual(true);
+  });
+
   it("should apply the name filter", async function () {
     // arrange
     const batchName = (await client.getBatches()).data[1]?.name ?? "test";