How can I measure my ring size without a ring sizer?

The most reliable at-home method is measuring the inside diameter of a ring that already fits the intended finger. String or paper-strip methods tend to stretch and read small. For the most accurate result, order a free plastic ring sizer from 25karats and wear it for a day or two.

What if I'm between two ring sizes?

Choose the larger of the two sizes: a slightly loose ring is comfortable and easy to adjust, while a tight one is hard to wear. Most gold and platinum rings can also be resized later if needed.

When is the best time to measure my ring size?

Measure at the end of the day at normal room temperature, when your fingers are at their typical size. Fingers run smaller in the morning and in cold weather, so check the size a few times over a couple of days.

Do wide bands fit differently?

Yes. Bands 6 mm and wider cover more of the finger and fit more snugly, so most people go up about half a size from their regular measurement. Whenever possible, measure with a sizer in the same width as the band you plan to buy.

Ring Size Guide

How to Measure Your Ring Size

Four easy ways to find your exact size from home: measure a ring you already own, order a free sizer, measure your finger, or convert an international size.

Measure a ring that fits

Match the inside diameter of a ring you already wear on that finger. This is the most reliable at-home method.

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Request a free ring sizer

We’ll mail you a reusable plastic sizer at no cost. It's the most accurate option before you order.

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Measure your finger

Use a strip of paper or string and our on-screen guide to size the finger directly.

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Convert from another country

Already know your UK, European, or Asian size? Convert it to your US size in seconds.

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Tips for an accurate measurement

Finger size isn’t fixed; it shifts with temperature, time of day, and band width. A few habits make the difference between a good guess and a confident fit:

Measure late in the day, more than once

Fingers are smaller in the morning and in cold weather. Measure at the end of the day at normal room temperature, and repeat over two or three days before settling on a size.

Account for your knuckle

If your knuckle is noticeably larger than the base of your finger, measure both and choose a size in between. The ring should pass over the knuckle with a little resistance, then sit snug.

Size up for wide bands

Bands 6 mm and wider fit more snugly than narrow ones. Most people go up about half a size, and ideally measure with a sizer in the same width as the band they’re buying.

Know what a good fit feels like

A well-fitted ring slides over the knuckle with minimal resistance, feels snug without pinching, doesn’t spin freely, and stays comfortable through a full day of wear.

Need to convert between US, UK, and European sizes? See our international ring size conversion chart.

Frequently asked questions

How can I measure my ring size without a sizer?

The most reliable at-home method is measuring the inside diameter of a ring that already fits the intended finger. String and paper-strip methods tend to stretch and read small, so if you have a few days, the free mailed sizer is worth the wait.

What if I’m between two sizes?

Choose the larger size. A slightly loose ring is comfortable and easy to adjust; a tight one is hard to wear. Most gold and platinum rings can also be resized later if needed.

Is it safe to guess my partner’s size for a surprise?

Borrow a ring they wear on the correct finger and use the “measure a ring that fits” tool above; no one has to know. If that’s not possible, the average size is around 6–7 for women and 9–10 for men, and we offer free resizing on most rings so a close guess isn’t a costly one.

Does 25karats really send ring sizers for free?

Yes. We mail a reusable plastic ring sizer at no cost, no purchase required. It’s the same tool we recommend to every customer before ordering a wedding band or engagement ring.