diff --git a/projects/composablekernel/include/ck/tensor_operation/gpu/device/impl/device_moe_gemm_blockscale.hpp b/projects/composablekernel/include/ck/tensor_operation/gpu/device/impl/device_moe_gemm_blockscale.hpp
index 12d28f572c5d..684219b58432 100644
--- a/projects/composablekernel/include/ck/tensor_operation/gpu/device/impl/device_moe_gemm_blockscale.hpp
+++ b/projects/composablekernel/include/ck/tensor_operation/gpu/device/impl/device_moe_gemm_blockscale.hpp
@@ -256,7 +256,8 @@ struct DeviceMoeGemmBlockScale
                         if(arg_.KBatch > 1)
                             hipGetErrorString(hipMemsetAsync(arg_.p_c_grid,
                                                              0,
-                                                             arg_.M * arg_.N * sizeof(CDataType) *
+                                                             arg_.NumTokens * arg_.TopK * arg_.N *
+                                                                 sizeof(CDataType) *
                                                                  (IsInputGemm && IsSplitK ? 2 : 1),
                                                              stream_config.stream_id_));
                     };
@@ -273,12 +274,12 @@ struct DeviceMoeGemmBlockScale
                 else
                 {
                     if(arg.KBatch > 1)
-                        hipGetErrorString(hipMemsetAsync(arg.p_c_grid,
-                                                         0,
-                                                         arg.M * arg.N * sizeof(CDataType) *
-                                                             (IsInputGemm && IsSplitK ? 2 : 1),
-                                                         stream_config.stream_id_));
-
+                        hipGetErrorString(
+                            hipMemsetAsync(arg.p_c_grid,
+                                           0,
+                                           arg.NumTokens * arg.TopK * arg.N * sizeof(CDataType) *
+                                               (IsInputGemm && IsSplitK ? 2 : 1),
+                                           stream_config.stream_id_));
                     ave_time = launch_and_time_kernel(
                         stream_config, kernel, dim3(gdx, gdy, gdz), dim3(BlockSize), 0, arg);
                 }