True Ring Size: Sizer & Gauge for iPhone and Android

Overview

What it is, in plain words.

True Ring Size: Sizer & Gauge turns your phone into a ring sizer without any physical tool. Place a ring on the screen, or line up guides to your finger, and read the size instantly. You calibrate once with any bank card for real-millimeter accuracy and then convert between US, UK, EU, Japan, China and Russia sizing, working offline and free.

What is it?

True Ring Size: Sizer & Gauge is an on-screen ring and finger sizer with a size converter and saved sizes.

What problem does it solve?

Buying a ring online, especially as a gift or an engagement ring, risks ordering the wrong size, and ring sizing systems differ by country. This app measures a ring or finger on the screen and converts the result to every common system.

Features

Everything it can do.

Ring on screen
Place a ring you already own on the display and resize the circle until it matches.
Finger on screen
Line up the guides to your finger and read the size instantly.
Card calibration
Calibrate once with any bank card for real-millimeter accuracy.
Size conversion
Convert between US, UK, EU, Japan, China and Russia sizing by diameter or circumference, in mm or inches.
Full size table
Look up a full conversion chart for every country system.
Saved sizes
Save sizes for the whole family, useful for surprise gifts and engagement rings.

Screenshots

See it up close.

How it works

Up and running in three steps.

Calibrate once
Match a bank card on the screen in Settings.
Measure
Lay a ring on the screen and resize the circle, or slide the guides to your finger at the knuckle.
Save and convert
Save the size and see it in every size system.

Who it is for

Is it for you?

Anyone buying an engagement ring, a wedding band or a gift online who wants to know the right size without visiting a jeweler. On-screen measuring depends on your display, so calibrate with a card and measure twice.

Get the app · App Store Get the app · Google Play

Privacy and permissions

Private by design.

The store listing says the app is fully offline, with no internet permission, no ads, no account, no tracking and no data collection, and that nothing leaves your phone. It is free forever with no subscription or in-app purchases.

Read the privacy policy

No ads
No tracking
Works offline

FAQ

Questions, answered.

Is the on-screen measurement accurate?

It depends on your screen. Calibrate once with a bank card and measure twice for best results. A finger is soft and oval, so finger measuring is approximate.

Which sizing systems does it support?

US, UK, EU, Japan, China and Russia, with conversion by diameter or circumference.

Do I need a physical ring sizer?

No. You can use a ring you already own or your finger.

Does it work offline?

Yes. It is 100% offline, with no internet permission.

Is it free?

Yes. The store listing says it is free forever, with no subscription, in-app purchases or ads.

Can I save sizes for other people?

Yes. You can save sizes for the whole family, which is handy for gifts.

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