diff --git a/csrc/cpu/pos_encoding.cpp b/csrc/cpu/pos_encoding.cpp
index 96bce7dd..8a59e884 100644
--- a/csrc/cpu/pos_encoding.cpp
+++ b/csrc/cpu/pos_encoding.cpp
@@ -170,7 +170,7 @@ void rotary_embedding_gptj_impl(
 void rotary_embedding(torch::Tensor& positions, torch::Tensor& query,
                       torch::Tensor& key, int64_t head_size,
                       torch::Tensor& cos_sin_cache, bool is_neox) {
-  int num_tokens = query.numel() / query.size(-1);
+  int num_tokens = positions.numel();
   int rot_dim = cos_sin_cache.size(1);
   int num_heads = query.size(-1) / head_size;
   int num_kv_heads = key.size(-1) / head_size;