diff --git a/router/src/infer.rs b/router/src/infer.rs
index d6dbd842..d7b9b52b 100644
--- a/router/src/infer.rs
+++ b/router/src/infer.rs
@@ -387,7 +387,7 @@ async fn batching_task(
                 };
 
                 let token_budget = max_batch_total_tokens.saturating_sub(batch_max_tokens);
-                let max_size = max_batch_size.map(|max_size| batch_size as usize - max_size);
+                let max_size = max_batch_size.map(|max_size| max_size - batch_size as usize);
 
                 // Try to get a new batch
                 if let Some((mut new_entries, new_batch, span)) = queue