Something not adding up? Ask.

Do I need an account?

No. Everything works without one. Sign in only to keep your sizes the same on your phone and your computer.

In the app, tap the gear to open Settings, tap Sync and sign in with Google or Apple. Or link your computer to your phone with a short code, no sign-in needed.

Does it work offline?

Yes. Typing a size, a screenshot and a photo of a tag all work offline.

Type what it is and its size, like “18L blender”, “55-inch TV” or “shoe size 36”. A few unusual words need a connection.

These need a connection: pasting a link, measuring on a sheet of A4 paper, signing in and sync.

Why does a result say Estimate, or that it assumed a unit?

Because the product page left something out. Every answer shows how sure it is.

• Verified Made to a standard size. A sheet of A4 paper is 210 × 297 ⁠mm wherever it’s sold.
• Typical A common size rather than a fixed one, like a plastic chair.
• Estimate The page gave no unit, or no size, so ThisBig used what that kind of thing usually measures.

“Unit assumed” means the page said 12 x 8 x 4 and nothing else. ThisBig picks the unit that makes sense. Tap the right one to redraw.

What are the extension’s permissions for?

Chrome and Edge warn about three of them. Here’s what each one does, in their words.

“Read and change your data on a number of websites”

The shops it knows, like Jumia, Amazon, AliExpress, eBay and Etsy, plus ThisBig’s own server. On a product page it reads the name, the size details and the size chart, then adds the answer under the title. It doesn’t read prices, photos or anything you type.

“Read and change all your data on all websites”

Asked for only if you turn on Every other site too in Settings, so it can do the same on shops it doesn’t know.

“Modify data you copy and paste”

Copies the drawing so you can paste it into a chat. It never reads what you’ve copied.

The rest, which show no warning

activeTab and scripting read the page you’re on when you click the ThisBig button or right-click a size. contextMenus adds that right-click item. sidePanel opens the drawing beside the page. storage keeps your sizes and settings in this browser. identity opens Google’s or Apple’s sign-in window, only if you choose to sign in. alarms checks once a day for new things to draw beside and, once you’ve linked your phone, syncs.

When it isn’t sure of a size, it sends the page’s link to ThisBig to read, without the part after the ?. To stop that, turn off Check unsure sizes online in Settings. The privacy policy lists everything it keeps and sends.

How do I delete my data?

In the app, tap the gear to open Settings. Delete my sizes clears them from the phone. If sync is on, Delete synced copy removes the synced copy, and Delete my account removes the account too. Uninstalling the app or removing the extension clears what it kept there.

No app? Use the deletion request form. What’s held, and for how long, is in the privacy policy.

I run a shop. Can my product pages show this?

Yes, with ThisBig for shops. It works on Shopify, WordPress or any site you can add two lines to. The plans are on the pricing page.