diff --git a/types/mongodb/index.d.ts b/types/mongodb/index.d.ts
index 3354845633..284ddb4956 100644
--- a/types/mongodb/index.d.ts
+++ b/types/mongodb/index.d.ts
@@ -28,6 +28,7 @@
 //                 Alberto Silva <https://github.com/albertossilva>
 //                 Rauno Viskus <https://github.com/Rauno56>
 //                 Piotr Błażejewicz <https://github.com/peterblazejewicz>
+//                 Linus Unnebäck <https://github.com/LinusU>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 3.0
 
@@ -1279,10 +1280,10 @@ export type PullAllOperator<TSchema> = ({
 export type UpdateQuery<TSchema> = {
     /** https://docs.mongodb.com/manual/reference/operator/update-field/ */
     $currentDate?: OnlyFieldsOfType<TSchema, Date, true | { $type: 'date' | 'timestamp' }>;
-    $inc?: OnlyFieldsOfType<TSchema, number>;
+    $inc?: OnlyFieldsOfType<TSchema, number | undefined>;
     $min?: MatchKeysAndValues<TSchema>;
     $max?: MatchKeysAndValues<TSchema>;
-    $mul?: OnlyFieldsOfType<TSchema, number>;
+    $mul?: OnlyFieldsOfType<TSchema, number | undefined>;
     $rename?: { [key: string]: string };
     $set?: MatchKeysAndValues<TSchema>;
     $setOnInsert?: MatchKeysAndValues<TSchema>;
diff --git a/types/mongodb/test/collection/updateX.ts b/types/mongodb/test/collection/updateX.ts
index 96864cc3d6..46711a602a 100644
--- a/types/mongodb/test/collection/updateX.ts
+++ b/types/mongodb/test/collection/updateX.ts
@@ -17,6 +17,7 @@ async function run() {
     interface TestModel {
         stringField: string;
         numberField: number;
+        optionalNumberField?: number;
         dateField: Date;
         otherDateField: Date;
         oneMoreDateField: Date;
@@ -44,6 +45,7 @@ async function run() {
     // buildUpdateQuery({ $currentDate: { stringField: true } }); // stringField is not a date Field
 
     buildUpdateQuery({ $inc: { numberField: 1 } });
+    buildUpdateQuery({ $inc: { optionalNumberField: 1 } });
     buildUpdateQuery({ $inc: { 'dot.notation': 2 } });
     buildUpdateQuery({ $inc: { 'subInterfaceArray.$': -10 } });
     buildUpdateQuery({ $inc: { 'subInterfaceArray.$[bla]': 40 } });
@@ -68,6 +70,7 @@ async function run() {
     // buildUpdateQuery({ $min: { numberField: 'a' } }); // Matches the type of the keys
 
     buildUpdateQuery({ $mul: { numberField: 1 } });
+    buildUpdateQuery({ $mul: { optionalNumberField: 1 } });
     buildUpdateQuery({ $mul: { 'dot.notation': 2 } });
     buildUpdateQuery({ $mul: { 'subInterfaceArray.$': -10 } });
     buildUpdateQuery({ $mul: { 'subInterfaceArray.$[bla]': 40 } });