diff --git a/include/ck_tile/ops/welford/block/block_welford.hpp b/include/ck_tile/ops/welford/block/block_welford.hpp
index 55d55402d8..623e1e16d8 100644
--- a/include/ck_tile/ops/welford/block/block_welford.hpp
+++ b/include/ck_tile/ops/welford/block/block_welford.hpp
@@ -276,8 +276,8 @@ struct BlockWelfordCrossWarpSync
         fp32x4_t all_scratch[thread_buf_size * num_reduce_warps];
         static_for<0, thread_buf_size, 1>{}([&](auto i_0) {
             static_for<0, num_reduce_warps, 1>{}([&](auto i_1) {
-                all_scratch[i_0 * num_warps + i_1] =
-                    smem_ptr[i_0 * num_reduce_warps + local_smem_os + i_1];
+                all_scratch[i_0 * num_reduce_warps + i_1] =
+                    smem_ptr[i_0 * num_warps + local_smem_os + i_1];
             });
         });
         block_sync_lds(); // TODO: we don't need sync here
@@ -286,7 +286,7 @@ struct BlockWelfordCrossWarpSync
 
         static_for<0, thread_buf_size, 1>{}([&](auto i_0) {
             // TODO: use descriptor for this
-            auto v_local       = all_scratch[i_0 * num_warps];
+            auto v_local       = all_scratch[i_0 * num_reduce_warps];
             auto v_local_mean  = bit_cast<DataType>(v_local[0]);
             auto v_local_var   = bit_cast<DataType>(v_local[1]);
             auto v_local_count = bit_cast<int>(v_local[2]);
@@ -294,7 +294,7 @@ struct BlockWelfordCrossWarpSync
             // further reduce mean/var
             static_for<0, num_reduce_warps - 1, 1>{}([&](auto i_1_n1) {
                 constexpr auto i_1        = number<i_1_n1 + 1>{};
-                const fp32x4_t v_remote   = all_scratch[i_0 * num_warps + i_1];
+                const fp32x4_t v_remote   = all_scratch[i_0 * num_reduce_warps + i_1];
                 const auto v_remote_mean  = bit_cast<DataType>(v_remote[0]);
                 const auto v_remote_var   = bit_cast<DataType>(v_remote[1]);
                 const auto v_remote_count = bit_cast<int>(v_remote[2]);