diff --git a/docs/en/api-guides/performance/speed.rst b/docs/en/api-guides/performance/speed.rst
index e16b612ec1..e1e5e9ab17 100644
--- a/docs/en/api-guides/performance/speed.rst
+++ b/docs/en/api-guides/performance/speed.rst
@@ -42,7 +42,7 @@ Otherwise, one way to measure performance is to augment the code to take timing
 
         uint64_t end = esp_timer_get_time();
 
-        printf("%u iterations took %ull milliseconds (%ull microseconds per invocation)\n",
+        printf("%u iterations took %llu milliseconds (%llu microseconds per invocation)\n",
                MEASUREMENTS, (end - start)/1000, (end - start)/MEASUREMENTS);
     }