Ring Sizer & Ring Size Chart

💍 What's your ring size? Find out in under a minute, at home, with the phone in your hand.

Most people guess their ring size, and a wrong guess means a resize, a return, or a ring that slips off. Ring Sizer measures it properly and gives you the answer in every system jewellers use.

Pick the way that suits you

💍 Have a ring that fits? Lay it on the screen and grow the circle until it meets the inside of the band. It is the most accurate way, and the classic trick for a surprise gift: borrow one of their rings for a minute.

✋ No ring? Rest your finger on the screen with its base at the bottom edge, then slide the lines with your other hand until they just touch its sides.

📏 Paper or string? Wrap it round your finger, mark where it meets, and lay it on the ruler on screen. Or simply type the length.

Your answer in every size system

US 7 is UK N½, EU 54, Swiss 14 and 17.3 mm across. Ring Sizer shows them all at once, plus the circumference, so whichever shop you buy from, you can match its chart. A full ring size chart is built in too, and any row opens that ring at true size on your screen.

Why you can trust the numbers

Phones often report their screen size slightly wrong, which is why so many ring sizing apps end up half a size out. Ring Sizer lets you check your screen once with any bank, ID or loyalty card. Those cards are exactly 85.60 by 53.98 mm everywhere in the world, so after one check every circle and ruler on your screen is true to the millimetre.

What a jeweller would tell you

Wide bands, 6 mm or more, sit tighter on the finger. Switch on Wide band and the app goes half a size up for you. Land between two sizes and it says so, naming both.

Everyone's size, saved

Keep sizes for yourself, a partner, Mum, Dad or a friend, and send one to someone in a single tap. Handy before an engagement, a wedding, an anniversary or a birthday.

Questions people ask

Is it accurate? Measuring a ring that already fits, after the card check, is the most accurate way to size a ring at home.

Does it work offline? Yes. Measuring needs no internet, and nothing you measure or save ever leaves your phone.

Is it free? Yes. Every way of measuring is free. A single purchase removes the ads.