diff --git a/nprogress/NProgress-tests.ts b/nprogress/NProgress-tests.ts
index d7ad68b39..3d07cafa2 100644
--- a/nprogress/NProgress-tests.ts
+++ b/nprogress/NProgress-tests.ts
@@ -3,6 +3,7 @@
 function test_basics() {
     NProgress.start();
     NProgress.inc();
+    NProgress.inc(0.2);
     NProgress.done();
     NProgress.set(0.5);
 
@@ -29,4 +30,4 @@ function test_configuration() {
         trickleRate: 0.42,
         trickleSpeed: 42
     });
-}
\ No newline at end of file
+}
diff --git a/nprogress/NProgress.d.ts b/nprogress/NProgress.d.ts
index a86558aae..6bad4cfd1 100644
--- a/nprogress/NProgress.d.ts
+++ b/nprogress/NProgress.d.ts
@@ -23,6 +23,13 @@ interface NProgressStatic {
      */
     inc(): NProgressStatic;
 
+    /**
+     * Increments the progress bar with a set amount.
+     * @param {number} amount This will get the current status value and adds the value until status is max 0.994
+     * @returns {NProgressConfigureOptions} The current NProgress object, useful for chaining.
+     */
+    inc(amount: number): NProgressStatic;
+
     /**
      * Removes the progress indicator.
      */
@@ -102,4 +109,4 @@ interface NProgressConfigureOptions {
     template?: string;
 }
 
-declare var NProgress: NProgressStatic;
\ No newline at end of file
+declare var NProgress: NProgressStatic;