diff --git a/pbkdf2/src/simple.rs b/pbkdf2/src/simple.rs
index 67061411..957f00b1 100644
--- a/pbkdf2/src/simple.rs
+++ b/pbkdf2/src/simple.rs
@@ -188,7 +188,7 @@ impl Params {
 impl Default for Params {
     fn default() -> Params {
         Params {
-            rounds: Self::RECOMMENDED_ROUNDS as usize,
+            rounds: Self::RECOMMENDED_ROUNDS as u32,
             output_length: 32,
         }
     }