Sheet Speed Checker

Name: Sheet Speed Checker
Availability: InStock

Find out why your Google Sheet™ is slow.

Free check. See where the seconds go — then fix the safe ones in a click.

Install: get it from the Google Workspace™ Marketplace, or in a sheet choose Extensions › Add-ons › Get add-ons and search for “Sheet Speed Checker”. It is an editor add-on for Google Sheets™ on desktop browsers — it does not run in the Google Sheets™ mobile apps. See how it works.

The top five causes of a slow sheet

Google documents what makes Sheets slow; this add-on finds which of them are in yours. The five it sees most:

Grid bloat — thousands of empty rows past the data that every recalculation still walks. What it means
External imports — IMPORTRANGE and friends waiting on the network, sometimes fetched dozens of times over. What it means
Volatile formulas — NOW, TODAY, RAND recalculating on every keystroke, with everything downstream. What it means
Conditional-format clutter — one rule split into hundreds of fragments by copy-paste, each evaluated on every change. What it means
Lookups over whole columns — VLOOKUP and XLOOKUP scanning A:A on a bloated tab. What it means

Ten more checks run alongside — duplicate imports, custom functions, validation ranges, calculation chains and the rest. See the guide for all fifteen.

Three steps

Install. Extensions › Add-ons › Get add-ons and search for the name.
Check. Open a spreadsheet, then Extensions › Sheet Speed Checker › Open checker. Press Check this sheet — free, unlimited, no key.
Fix. Every finding explains what it costs and why. The safe ones have a fix with a preview of the exact change before anything is written — and Undo is always there if you change your mind.

Free and Pro

Free

£0

Unlimited checks of the active sheet
The grade and the “where the time goes” bars
Every finding and explanation, with click-to-cell
Every fix preview
Undo — always, in every tier

Pro

£29 per year, or £4 a month

Everything in Free
Every fix: trim, recalculation, freeze, format merge
Check every tab in the spreadsheet
A report tab written into the file
3 activations

Prices and checkout

Your data

Your spreadsheet content never leaves Google. The checks run in the sidebar, in your browser. The only network traffic this add-on makes is to the licence server, and only a licence key, an anonymous install id and which host this is ever cross it. The add-on asks for this spreadsheet only — not your Drive, not your other files. Privacy notice.

FAQ

Does my data leave Google? No. Checking and fixing both happen in the sidebar, against the Sheets API, without your content going anywhere else.

Will it change my sheet? Only when you click a Fix — and every fix previews the exact change first, takes a restore point, and can be undone free.

Is the grade a real timing? It is an estimate from a cost model, and the sidebar says so honestly. It never promises a speedup it cannot measure.

Does it work with Gmail™ and Workspace accounts? Yes, both — though a Workspace admin can block add-ons entirely, in which case the listing simply does not appear.

What about the 20-million-cell limit? One of the checks watches it: near the limit, the finding says so and trimming empty grid buys headroom.

What if I want to undo a fix? Every fix saves a hidden copy of the tab first. Press Undo in the sidebar to restore it, in any tier, at any time.

Support

Email support@appgarden.co.uk. Say which finding looked wrong and include, if you can share it, a copy of the sheet with the problem — read the privacy notice first.

Also from AppGarden for Google Sheets™: AI Readiness Scanner and Fixer and Hardcoded Value Detector.

Articles

Google, Google Sheets™ and Google Workspace™ are trademarks of Google LLC. Sheet Speed Checker is not affiliated with or endorsed by Google.