To measure your ring size at home, wrap a strip of paper or string around the base of your finger, mark where it overlaps, measure that length in millimeters, and match it to a ring size chart. For the most accurate result, measure at the end of the day when your fingers are at their largest, take two or three readings, and make sure the strip slides over your knuckle. A printable ring sizer or an existing well-fitting ring gives even better accuracy.
Getting your ring size right is the one step you can't afford to guess — a band that's too tight is uncomfortable and hard to remove, while one that's too loose can slip off and be lost. The good news is that you can measure accurately at home in a couple of minutes with things you already own. This guide walks through four reliable methods, shows you how to convert your measurement into a ring size, and shares the timing tricks jewelers use so your first fit is the right one. When you have your size, you'll be ready to browse — for coordinated pairs, see our collection of his and hers wedding bands.
1. Before you start: timing tips
Fingers are not a fixed size, and measuring at the wrong moment is the most common reason a ring arrives too tight or too loose. Three factors change your finger size through the day, and getting them right matters more than the method you choose.
Time of day. Fingers are smallest first thing in the morning and swell slightly as the day goes on. Measure at the end of the day, when your finger is at its typical, relaxed size, for the most reliable everyday fit.
Temperature. Cold shrinks your fingers and heat expands them. Measure when you're at a normal room temperature, not straight after coming in from the cold or after a hot shower or exercise.
Body factors. Salty food, alcohol, and for some people the time of the month can cause temporary swelling. Measure on an ordinary day when you feel normal, and take the reading two or three times to be sure it's consistent. Also remember to size the correct finger — the ring finger on the correct hand — since your dominant hand is often slightly larger.
2. Method 1: paper or string
This is the quickest method and needs nothing more than a strip of paper (or a piece of string or floss), a pen, and a ruler.
- Cut a thin strip of paper about 10 cm long and 5 mm wide, or use a length of string.
- Wrap it snugly around the base of your finger — snug, not tight.
- Mark the point where the strip overlaps and forms a complete circle.
- Check it slides over your knuckle while wrapped; if not, loosen slightly so the ring will pass over.
- Lay the strip flat and measure the length up to your mark in millimeters. That's your finger's circumference.
- Match the millimeter figure to a ring size using our ring size chart.
The one caution with this method: paper and string can stretch or pinch, so take a few readings and use the largest consistent one so the ring clears your knuckle.
3. Method 2: printable ring sizer
A printable ring sizer is a small paper tool you print, cut out, and use like an adjustable belt around your finger. It's more accurate than a plain paper strip because the sizes are pre-marked, so there's no conversion step or ruler error.
- Print the sizer at 100% scale — do not select "fit to page," which distorts the measurements. Check the printed ruler against a physical one to confirm the scale is correct.
- Cut out the strip and the small slot it threads through.
- Wrap it around the base of your finger and thread the pointed end through the slot.
- Pull it snug and check it passes over your knuckle.
- Read the size shown at the slot — that's your ring size, no conversion needed.
Because accuracy depends entirely on printing at true scale, always verify with the printed test ruler before trusting the result. We can provide a printable sizer on request — ask our team.
4. Method 3: measure a ring that fits
If you already own a ring that fits the correct finger well, this is often the most accurate and least fiddly method — and it's the ideal way to size a partner's finger discreetly for a surprise.
- Choose a ring that fits the finger you're buying for, worn comfortably.
- Measure the inside diameter across the widest point in millimeters, using a ruler held against the ring's inner edge.
- Measure two or three times and take the average for accuracy.
- Match the inside-diameter figure to a size on our ring size chart.
Take care to measure a ring that sits on the same finger you're buying for — sizes differ noticeably between fingers and hands, so a ring from a different finger will mislead you.
5. Method 4: inside-diameter measurement
This is a variation of the ring-that-fits method for when you want to be precise. Rather than eyeballing the diameter with a ruler, place the ring over a series of printed circles (many charts include these) until you find the circle whose edge lines up exactly with the inside of the band. The size printed beside that circle is your answer. It removes the small parallax error that comes from measuring a curved inner edge with a straight ruler, and it's the method we recommend if you're between two sizes on the string test.
Shop his and hers wedding bands →6. Converting to a ring size
Whatever method you use, you'll end up with either a circumference (the distance around your finger) or a diameter (the distance across the inside of a ring). Both convert to a standard ring size, but the systems differ by country: the US and Canada use a numeric scale, the UK and Australia use letters, and much of Europe uses the circumference in millimeters directly.
Rather than reproduce the whole conversion here, we keep a complete, up-to-date reference in one place. Our ring size chart lists every US, UK, and EU size alongside its circumference and inside diameter in millimeters, with a printable version — bookmark it as your conversion companion to this guide. The short version below shows how the systems line up at a few common sizes.
| Circumference (mm) | US size | UK size | Inside diameter (mm) |
|---|---|---|---|
| ~51.9 | 6 | L½ | ~16.5 |
| ~54.4 | 7 | N½ | ~17.3 |
| ~57.0 | 8 | P½ | ~18.1 |
| ~59.5 | 9 | R½ | ~18.9 |
| ~62.1 | 10 | T½ | ~19.8 |
Figures are approximate — see the full ring size chart for every size and precise measurements.
7. Half sizes, width, and comfort fit
Two details catch people out. First, half sizes exist for a reason: if your measurement falls between two whole sizes, choose the half size rather than rounding, or size up slightly so the ring clears your knuckle. A ring should slide on with a little resistance and come off over the knuckle with a gentle tug.
Second, the band itself affects the fit. Wider bands feel tighter than narrow ones at the same nominal size, so if you're choosing a band of 6 mm or more, consider sizing up by a quarter to a half. And crucially, comfort-fit bands — those with a domed interior — typically measure about half a size smaller than standard-fit rings, so always confirm your size against the exact style you're ordering. Our main wedding band buying guide explains width, profile, and comfort fit in full.
8. What if it still doesn't fit?
Even with careful measuring, occasionally a first fit isn't perfect, and that's normal — it's why you should order early, around 8 to 12 weeks before a wedding, to leave time for adjustment. Most metals can be resized by a jeweler within a range of sizes, though some designs, particularly bands set with stones all the way around (eternity or full-pavé styles), have limited resizing options because the pattern can't easily be stretched or cut.
If you're sizing two rings for a couple, measure each finger separately and don't assume both partners are close in size — they rarely are. Our matching bands guide covers sizing a pair, and check any specific ring's resizing policy before you buy. When in doubt, our team is happy to advise on the best size for a particular style.
Find your pair: his and hers wedding bands →9. Frequently asked questions
- How can I measure my ring size at home without a sizer?
- Wrap a strip of paper or string around the base of your finger, mark the overlap, and measure that length in millimeters — that's your circumference. Match it to a size using our ring size chart. Take a few readings and make sure it slides over your knuckle.
- What time of day should I measure my finger?
- At the end of the day, when your fingers are at their largest and most typical size, at a normal room temperature. Avoid measuring when cold, after exercise, or after salty food.
- How do I find someone's ring size secretly?
- Borrow a ring they already wear on the correct finger and measure its inside diameter, then match it to our ring size chart. Make sure it's from the same finger you're buying for.
- Should I size up for a wide band?
- Yes. Wider bands (6 mm and up) feel tighter than narrow ones, so consider sizing up by a quarter to a half. Comfort-fit bands run about half a size smaller, so confirm against the exact style.
- Can a wedding band be resized later?
- Most bands can be resized within a range, but fully stone-set styles like eternity bands have limited options. Order 8–12 weeks before the wedding so there's time to adjust, and check the resizing policy on your chosen ring.
- Where can I find the full size conversion chart?
- Our ring size chart lists every US, UK, and EU size with circumference and diameter in millimeters, plus a printable version — it's the reference companion to this how-to guide.
