Ringmate: Ring Size Finder

Find your ring size at home with just your phone. Lay a ring on the screen, match the circle to its inner edge, and see your size in US, UK, EU, Japanese, Korean and Swiss systems at once.

Why most ring sizer apps get it wrong: every phone screen is a slightly different size. Ringmate fixes that. Hold any bank card or ID card to the on-screen frame once, and every circle you see after that is true to size on your phone.

MEASURE A RING
• Place a ring you already own on the circle
• Drag the slider or tap −/+ in 0.1 mm steps until the line sits on the inner edge
• Your size appears instantly, with the inner diameter in mm

NO RING? MEASURE YOUR FINGER
• Lay your finger between two lines and match its width
• Handy for a surprise gift or an engagement ring

EVERY SIZE SYSTEM, SIDE BY SIDE
• US & Canada, UK & Australia, EU (ISO), Japan, Korea, Switzerland
• A full ring size chart with half sizes and diameters
• Pick your main system once — it shows first everywhere

SAVE SIZES FOR EVERYONE
• Save yours, your partner's and your family's sizes by hand and finger
• Share a clean ring size card with the person buying the ring
• Home-screen widget shows your saved size at a glance

MEASURE AS OFTEN AS YOU LIKE
There is no limit on measurements and no paywall after the first try. Mess up? Just measure again.

PRIVATE BY DESIGN
No account. No camera. Card calibration never scans or stores your card — you can cover the number. Your sizes stay on your phone.

Tips for an accurate ring size
• Fingers are slightly bigger in the evening and in warm weather
• Between two sizes? Choose the bigger one, especially for wide bands
• Measure the same finger two or three times for a steady result

Ringmate is a measuring aid. For expensive or custom rings, confirm the size with your jeweler.

Recent changes:
First release: measure a ring or finger, card calibration, every size system, saved sizes and a home-screen widget.