Stop collaborators overwriting your formulas.
FormulaLock locks the cells you pick in Google Sheets in one click: it colours them, adds Google's edit warning, and puts them back automatically if someone changes them anyway.
Install free Get Pro, $19 once
| Rent | 1,200 |
| Food | 430 |
| Total | =SUM(B1:B2) |
Yellow = locked. Type over it and it comes back.
How it works
1. Select, lock
Select cells, then FormulaLock > Lock selected cells. Or lock every formula on a tab at once, while the input cells stay editable.
2. Everyone can see it
Locked cells get a yellow fill. Cells locked with Lock selected cells also get Google's own "are you sure?" edit warning.
3. Restore on edit
If a collaborator types or pastes over a locked cell, the original formula or value goes back and the change is logged.
4. Strict when you need it
One more click turns a lock into a hard protected range that only you can edit.
Your own edits to a locked cell (as the person who locked it) become the new locked version, so you never fight the tool.
What it can't do
It is not encryption and it does not hide anything: anyone who can view the sheet can still read and copy your formulas. Anyone with edit access can remove the script. Edits made by imports, other scripts or the Sheets API aren't caught. Full list.
Pricing
Pro, lifetime
Locks on every tab of every spreadsheet you use it in. One payment, no subscription. Key shown right after checkout.
Buy Pro, $1914-day full refund, no questions. Refunds
FAQ
Is it a Chrome extension?
Not yet. FormulaLock is a Google Apps Script you paste into your sheet once (Extensions > Apps Script). It takes about a minute, the code is readable, and it runs in your Google account only. Install steps.
Does it send my data anywhere?
No. Locks and saved formulas stay inside your spreadsheet's own script storage. The only network call is when you enter a Pro key, which sends the key to formulalock.com to check it.
What permissions does it ask for?
Three: the spreadsheet it is installed in only (to lock and restore cells), your email address (so your own edits count as the owner's and aren't reverted), and connecting to an external service (only for the licence key check).