diff --git a/types/parse-unit/index.d.ts b/types/parse-unit/index.d.ts
index 238f3cfc06..7b37d0e64b 100644
--- a/types/parse-unit/index.d.ts
+++ b/types/parse-unit/index.d.ts
@@ -3,5 +3,5 @@
 // Definitions by: Jack Works <https://github.com/Jack-Works>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-declare function parse(value: string): [number, string];
+declare function parse(value: string | number): [number, string];
 export = parse;
diff --git a/types/parse-unit/parse-unit-tests.ts b/types/parse-unit/parse-unit-tests.ts
index dd5dcb7e9f..5cd4b180b8 100644
--- a/types/parse-unit/parse-unit-tests.ts
+++ b/types/parse-unit/parse-unit-tests.ts
@@ -2,3 +2,7 @@ import parse = require('parse-unit');
 const [number, length] = parse('10px');
 number === 50;
 length === 'px';
+
+parse(10).length === 2;
+parse(10)[0] === 10;
+parse(10)[1] === '';