diff --git a/lmformatenforcer/integrations/transformers.py b/lmformatenforcer/integrations/transformers.py
index 839270e..7bcbc97 100644
--- a/lmformatenforcer/integrations/transformers.py
+++ b/lmformatenforcer/integrations/transformers.py
@@ -55,7 +55,7 @@ def unreplace_logits_warper(self):
 def _build_regular_tokens_list(tokenizer: PreTrainedTokenizerBase) -> List[Tuple[int, str, bool]]:
     token_0 = tokenizer.encode("0")[-1]
     regular_tokens = []
-    for token_idx in range(tokenizer.vocab_size):
+    for token_idx in range(len(tokenizer)):
         if token_idx in tokenizer.all_special_ids:
             continue
         # We prepend token 0 and skip the first letter of the result to get a space if the token is a start word.