Social Media Username Rules 2026: Character Limits by Platform

You finally settle on a name, go to claim the handle, and the platform rejects it: too long, contains a period, already reserved. Or worse, you rename an account and discover you cannot change it back for a month. Username rules feel arbitrary because every platform wrote its own, and they rarely match.

This is the reference. Real character limits, real allowed-symbol sets, and the rename rules that actually catch people off guard, each one checked against the platform's own pages: its help center where it publishes rules, and its sign-up form where it does not. The tables below render from the same verified data as our username format validator and every platform checker, so they change when a platform changes its rules.

Username Length and Characters at a Glance

Two numbers do most of the work. X and Snapchat both cap handles at 15 characters, the tightest maximum of the major platforms. X and Telegram both require at least 5 for a new name, the strictest minimum. Anything between 5 and 15 clears every platform on length.

The Handle That Fits Everywhere

If you want one identical handle on every platform, the rules above reduce to a short formula. Each constraint comes from a specific platform:

A name that passes all four can be claimed identically everywhere, as long as nobody else holds it. Checking that part is what our cross-platform availability search does.

How Often You Can Change It, and What Happens to the Old Name

Length limits are easy to plan around. Rename rules are the ones that bite later, because a rename is not always reversible and your old name does not always come back to you.

The X row is why renamed accounts are a steady source of newly free short handles: X's own help page says a changed-away username is available to others right away. Snapchat is the opposite: a name you leave is never released, not even back to you, and Roblox keeps old names on the account that used them. Reddit is stricter still, which is why it has no row: Reddit's help center says a finalized username cannot be changed in any way, including its capitalization.

Platform by Platform

X / Twitter

X is the strictest on length. Its username rules allow only letters, numbers and underscores, cap handles at 15 characters, and require a new username to be more than 4 characters long. Shorter handles you see on X belong to older accounts or came through X's own Handle Marketplace; you cannot pick one through a normal rename. X also blocks terms such as "admin" and "twitter" to prevent impersonation, and lets you rename any time.

Instagram

Instagram does not publish its username rules. Its help center explains how to change a username but never lists what one may contain, so the rules here are what Instagram's own sign-up form enforces, checked in October 2026: up to 30 characters using letters, numbers, periods and underscores, no period at the start or end, and never two periods in a row. Instagram stores every username in lowercase. You can change your username from Edit Profile at any time. Instagram's help center also says a recently freed username is temporarily blocked before anyone else can claim it, without publishing how long.

Threads

Threads publishes no username rules of its own either. A profile created with Instagram follows Instagram's rules, but the two names no longer have to match: Meta also lets you create a Threads profile with an email address or phone number, and you can change a Threads username from Edit profile. What still ties the two apps together is covered in our Threads username checker.

TikTok

TikTok allows usernames from 2 to 24 characters using letters, numbers, underscores and periods. The only position rule TikTok publishes is that a username cannot end with a period. The rule that surprises people is the cooldown: TikTok lets you change your username only once every 30 days. Your display name is separate and can be changed freely, but the @username itself is locked for a month after each change, so a typo can cost you 30 days.

YouTube

YouTube handles run 3 to 30 characters and are the most symbol-flexible of the big platforms: letters, numbers, underscores, hyphens, periods and middle dots. According to YouTube's handle documentation, a handle cannot start or end with a separator or look like a URL or phone number, and some scripts allow shorter handles. You can change your handle twice in any 14-day window, and an old handle is held for 14 days before anyone else can take it.

Snapchat

Snapchat allows 3 to 15 characters: letters and numbers plus a single hyphen, underscore or period. A username must start with a letter, end with a letter or number, and cannot be or contain a phone number. Snapchat allows one username change per year, and a username you leave is never released, so treat a Snapchat rename as permanent.

Telegram

Telegram usernames run 5 to 32 characters using letters, numbers and underscores (Telegram's FAQ covers the basics). A username must start with a letter, and cannot end with an underscore or contain two in a row. There is no rename cooldown, and short or memorable names are also traded as collectibles, which we track in the Telegram username market.

Twitch and Kick

Both streaming platforms allow 4 to 25 characters of letters, numbers and underscores, and both limit renames to once every 60 days (Kick also requires two-factor authentication first). Both have 3-letter accounts from their early days, but neither lets you register a new 3-letter name today.

Reddit, Pinterest, GitHub, Bluesky and Roblox

• Reddit: 3 to 20 characters, letters, numbers, underscores and hyphens, and permanent once set.
• Pinterest: 3 to 30 characters, letters, numbers and underscores, and it cannot be entirely numeric.
• GitHub: up to 39 characters, letters, numbers and single hyphens, never at the start or end. GitHub's docs note that your old username becomes available to others after a change.
• Bluesky: a short handle is 3 to 18 characters before the .bsky.social suffix, using letters, numbers and hyphens. You can also use a domain you own as your handle, which sidesteps the shared namespace entirely.
• Roblox: 3 to 20 characters, letters and numbers plus at most one underscore that cannot be first or last. Every name passes a content filter, and short names are almost entirely gone: our census of all 456,976 four-letter names found none that can be registered.

Does Capitalization Matter in a Username?

Not for uniqueness. On every platform in this guide, @BrandName and @brandname are the same handle, so you cannot register a capitalized copy of a taken name. What differs is display: Instagram and TikTok store usernames in lowercase, while X shows the capitalization you chose. Reddit locks capitalization along with the name, so decide it before you finalize. If your name is several words, capitalizing each word helps readability wherever the platform keeps your casing, and on lowercase-only platforms put the readable version in your display name.

Frequently Asked Questions

The Bottom Line

There is no universal username standard, only a different rulebook on every platform. Length and characters are the easy part: 5 to 15 characters, letters and numbers, starting with a letter, clears every major platform. The rules worth remembering are the ones that bite later: reserved words that block an otherwise-free name, and rename limits that make a change slow or impossible to undo. Check the exact rules before you commit, not after you have printed the name on something. If your ideal name breaks a rule, you usually just need a smart variant; we cover patterns that stay readable in creative username ideas for brands, and the cross-platform search process in how to check if a username is available.