diff --git a/src/Client/GRPC/BaseClient.php b/src/Client/GRPC/BaseClient.php
index 78cc3ef4..7b96da82 100644
--- a/src/Client/GRPC/BaseClient.php
+++ b/src/Client/GRPC/BaseClient.php
@@ -328,7 +328,7 @@ private function call(string $method, object $arg, ContextInterface $ctx): objec
                     ? $congestionInitialIntervalMs
                     : $initialIntervalMs;
 
-                $wait = $throttler->calculateSleepTime(failureCount: $attempt, initialInterval: $baseInterval);
+                $wait = $throttler->calculateSleepTime(failureCount: $attempt, initialInterval: $baseInterval) * 1000;
 
                 // wait till the next call
                 $this->usleep($wait);