diff --git a/backends/vulkan/runtime/api/containers/Tensor.h b/backends/vulkan/runtime/api/containers/Tensor.h
index 301666f45c6..30c243aedd5 100644
--- a/backends/vulkan/runtime/api/containers/Tensor.h
+++ b/backends/vulkan/runtime/api/containers/Tensor.h
@@ -523,6 +523,16 @@ class vTensor final {
     return packed_dim_info_.packed_dim;
   }
 
+  /*
+   * Returns the WHCN index of the fastest moving dimension (dim_order[0]).
+   * This is the dimension with stride 1 in the buffer layout.
+   * Note: dim_order_ is in NCHW order, so we convert to WHCN (3 - nchw_dim).
+   */
+  inline int32_t fastest_whcn_dim() const {
+    return packed_dim_info_.block_transposed ? packed_dim_info_.outer_packed_dim
+                                             : packed_dim_info_.packed_dim;
+  }
+
   inline const PackedDimInfo& packed_dim_info() const {
     return packed_dim_info_;
   }
diff --git a/backends/vulkan/runtime/graph/ComputeGraph.h b/backends/vulkan/runtime/graph/ComputeGraph.h
index 2231b78964a..a7c8cffffd1 100644
--- a/backends/vulkan/runtime/graph/ComputeGraph.h
+++ b/backends/vulkan/runtime/graph/ComputeGraph.h
@@ -456,6 +456,10 @@ class ComputeGraph final {
     return values_.at(idx).toConstTensor().packed_dim();
   }
 
+  inline int32_t fastest_whcn_dim_of(const ValueRef idx) const {
+    return values_.at(idx).toConstTensor().fastest_whcn_dim();
+  }
+
   inline const api::PackedDimInfo& packed_dim_info_of(
       const ValueRef idx) const {
     return values_.at(idx).toConstTensor().packed_dim_info();
diff --git a/backends/vulkan/runtime/graph/ops/glsl/indexing.glslh b/backends/vulkan/runtime/graph/ops/glsl/indexing.glslh
index 24f050b694e..16c4112547c 100644
--- a/backends/vulkan/runtime/graph/ops/glsl/indexing.glslh
+++ b/backends/vulkan/runtime/graph/ops/glsl/indexing.glslh
@@ -70,6 +70,8 @@ bool is_channels_last(const int hashed_layout) {
   return layout_id(hashed_layout) == CHANNELS_LAST_BUFFER_LAYOUT_ID;
 }
 
+#define get_fastest_dim(layout) ((layout) & 0xF)
+
 // Extract packed dim info from hashed_layout (bits 16-31)
 // These match the format created by create_hashed_layout() in Tensor.cpp
 #define get_packed_dim(layout) (((layout) >> 16) & 0xF)