Measure Pro

Ring sizer app: find a ring size on your screen

The Ring Size tool sizes a ring you already have. Place the ring on the circle on your screen and change the size of the circle until it touches the inside edge of the ring. The app shows the inner diameter and the US, UK, EU and Japanese size. The sizes are approximate, so ask a jeweller to check the size before you buy.

How to use it

1. Choose Ring Size in the tool strip.
2. Place a ring flat on the circle.
3. Slide the control until the circle touches the inside edge of the ring.
4. Read the inner diameter, the distance around, and the size in four systems.

Good for

• Finding the size of a ring you already wear before buying another
• Converting between US, UK, EU and Japanese sizes. The ring size chart does this too

What it can’t do

• Sizes are approximate. A wide ring band and swollen fingers both change the result.
• It sizes a ring, not a finger. Ask a jeweller to check the size before you buy.
• The circle is drawn at real size using each iPhone and iPad model’s screen density. On a model the app doesn’t recognise yet, it uses a typical value, so it can be slightly off.