diff --git a/packages/@aws-cdk/aws-rds/lib/instance.ts b/packages/@aws-cdk/aws-rds/lib/instance.ts
index c5a59c709517d..9b94564122ff2 100644
--- a/packages/@aws-cdk/aws-rds/lib/instance.ts
+++ b/packages/@aws-cdk/aws-rds/lib/instance.ts
@@ -813,7 +813,7 @@ export interface DatabaseInstanceSourceProps extends DatabaseInstanceNewProps {
   readonly timezone?: string;
 
   /**
-   * The allocated storage size, specified in gigabytes (GB).
+   * The allocated storage size, specified in gibibytes (GiB).
    *
    * @default 100
    */