Become the Biggest Brainrot Codes (December 2025)

Become the Biggest Brainrot lets you grow your brainrot by training and rebirthing; promo codes grant bonus Size and useful potions.

Updated: December 19, 2025.

New codes: Update4, 5MVisits, Speed

Update4 — Free Size boost and access to new update rewards NEW
5MVisits — Free Size or reward items to celebrate 5M visits NEW
Speed — Free reward that increases your movement speed NEW
Update3 — Extra Size to help your brainrot grow faster

How to redeem codes

Step 1: Open Roblox and launch Become the biggest brainrot. Wait until your character fully loads into the game world.

Step 2: Look at the right side of your screen and click the Shop button to open the in-game shop menu.

Step 3: Scroll down within the Shop menu until you find the Codes or code entry section with an Enter code text box.

Step 4: Click the text box, then carefully type or paste one working code exactly as shown above.

Step 5: Press the Redeem (sometimes labeled “Reddem”) button next to the box. If the code is valid and unused, your rewards are added to your account immediately.

Expired codes

1MVisits — Former milestone reward for 1M visits
Update2 — Old update reward that is no longer active

Why codes might not work

The code has expired and is no longer accepted by the game.
There is a typo, missing character, or extra space; codes are case-sensitive and must match exactly.
The code was already redeemed on your Roblox account, so it cannot be used again.
The server or your game session has not refreshed; closing Roblox and rejoining the experience can help.

Where to find more codes

New Become the Biggest Brainrot codes are shared by the developers from time to time, usually around updates and milestones. The main place to watch is the official The Biggest Brainrot Roblox group, where announcements often include fresh codes.

Bookmark this page — the working list is reviewed and updated regularly.

Codes in Become the Biggest Brainrot are case-sensitive and time-limited. Enter them exactly as written, redeem them as soon as you can, and avoid any third-party “code generator” sites or tools, as they are unsafe and cannot create real Roblox promo codes.