diff --git a/src/controllers/authentication.js b/src/controllers/authentication.js
index b7873b6a28..f948e053b5 100644
--- a/src/controllers/authentication.js
+++ b/src/controllers/authentication.js
@@ -84,17 +84,7 @@ authenticationController.register = async function (req, res) {
 			await user.verifyInvitation(userData);
 		}
 
-		if (
-			!userData.username ||
-			userData.username.length < meta.config.minimumUsernameLength ||
-			slugify(userData.username).length < meta.config.minimumUsernameLength
-		) {
-			throw new Error('[[error:username-too-short]]');
-		}
-
-		if (userData.username.length > meta.config.maximumUsernameLength) {
-			throw new Error('[[error:username-too-long]]');
-		}
+		user.checkUsernameLength(userData.username);
 
 		if (userData.password !== userData['password-confirm']) {
 			throw new Error('[[user:change-password-error-match]]');
diff --git a/src/user/profile.js b/src/user/profile.js
index ec4a23d3a3..b5e878eafa 100644
--- a/src/user/profile.js
+++ b/src/user/profile.js
@@ -170,13 +170,7 @@ module.exports = function (User) {
 			}
 		}
 
-		if (data.username.length < meta.config.minimumUsernameLength) {
-			throw new Error('[[error:username-too-short]]');
-		}
-
-		if (data.username.length > meta.config.maximumUsernameLength) {
-			throw new Error('[[error:username-too-long]]');
-		}
+		User.checkUsernameLength(data.username);
 
 		const userslug = slugify(data.username);
 		if (!utils.isUserNameValid(data.username) || !userslug) {
@@ -201,6 +195,20 @@ module.exports = function (User) {
 	}
 	User.checkUsername = async username => isUsernameAvailable({ username });
 
+	User.checkUsernameLength = function (username) {
+		if (
+			!username ||
+			username.length < meta.config.minimumUsernameLength ||
+			slugify(username).length < meta.config.minimumUsernameLength
+		) {
+			throw new Error('[[error:username-too-short]]');
+		}
+
+		if (username.length > meta.config.maximumUsernameLength) {
+			throw new Error('[[error:username-too-long]]');
+		}
+	};
+
 	async function isAboutMeValid(callerUid, data) {
 		if (!data.aboutme) {
 			return;