diff --git a/pythainlp/transliterate/w2p.py b/pythainlp/transliterate/w2p.py
index ccf0b018b..aa3a9ade0 100644
--- a/pythainlp/transliterate/w2p.py
+++ b/pythainlp/transliterate/w2p.py
@@ -294,7 +294,7 @@ def _predict(self, word: str) -> str:
         h = last_hidden
 
         preds: list[int] = []
-        for _ in range(20):
+        for _ in range(hp.dec_maxlen):
             h = self._grucell(
                 dec,
                 h,