How to Measure Your Ring Size at Home (Without a Ring Sizer)
If you're buying a ring online, the first thing you need to know is your ring size. The second thing you need to know is that almost every blog post telling you how to measure it at home is giving you bad advice. The Gemological Institute of America (GIA) explicitly warns against the most popular at-home methods, because string stretches, paper tears, and your finger changes size three times before lunch.
So what does work? We size around 200 rings a year at our bench in Coquitlam, and the honest answer is: nothing you do at home will be as accurate as a steel ring sizer. But you can get close enough to order with confidence, as long as you know where the traps are.
The fastest accurate option: get a free plastic ring sizer
This is what we tell every customer who can't make it into the shop. A plastic adjustable ring sizer (sometimes called a "finger gauge") costs about three dollars on Amazon, ships in two days, and is the same tool a jeweler would hand you across the counter. Slide it on, tighten it down to a snug fit, read the number. Done.
If you're in a real hurry, we'll mail one for free if you message us. It's faster than any string trick, and the result is a number you can actually trust.
If you have to measure today: the printable strip method
The string method is unreliable because string stretches in two directions. Paper, marked carefully, doesn't. Here's the version we recommend if you absolutely cannot wait:
- Cut a thin strip of plain printer paper, about 6mm wide and 100mm long.
- Wrap it snugly around the base of the finger you'll wear the ring on. Snug, not tight. You should be able to twist it slightly but not slide it off without bending your knuckle.
- Mark where the paper overlaps with a pen. Make the mark sharp.
- Lay the strip flat on a ruler and measure the distance from the edge to the mark, in millimetres.
- That number is your finger circumference. Match it to the chart below.
Do this three times on three different days, at different times of day. Take the largest of the three measurements. Why? Because of the trap GIA mentions: fingers swell in heat and shrink in cold. A ring sized to your finger on a January morning won't fit the same finger in August. Always size for your largest finger state, not your smallest. A slightly loose ring is uncomfortable. A ring that won't come off your swollen finger in summer is a trip to the emergency room.
Ring size chart: US/Canada to millimetres
Vanhess uses US/Canada sizing. Most North American jewellers do. If you're shopping internationally, the right column gives you the conversion to ISO 8653:2016, which is the metric standard used in Europe.
| US/Canada size | Inner diameter (mm) | Inner circumference (mm) |
|---|---|---|
| 4 | 14.88 | 46.8 |
| 4.5 | 15.29 | 48.0 |
| 5 | 15.70 | 49.3 |
| 5.5 | 16.10 | 50.6 |
| 6 | 16.51 | 51.9 |
| 6.5 | 16.92 | 53.1 |
| 7 | 17.32 | 54.4 |
| 7.5 | 17.73 | 55.7 |
| 8 | 18.14 | 57.0 |
| 8.5 | 18.54 | 58.3 |
| 9 | 18.95 | 59.5 |
| 9.5 | 19.35 | 60.8 |
| 10 | 19.76 | 62.1 |
| 10.5 | 20.17 | 63.4 |
| 11 | 20.57 | 64.6 |
| 11.5 | 20.98 | 65.9 |
| 12 | 21.39 | 67.2 |
| 13 | 22.20 | 69.7 |
Source: ISO 8653:2016 standard, via the published ring size reference table. Each whole size differs by 0.81 mm of inner diameter, equivalent to 2.55 mm of inner circumference.
Five ways people get this wrong
Measuring once. Your fingers are not the same size in the morning as they are after a salty meal. One measurement is not data, it's a coin flip.
Sizing the wrong finger. Your dominant hand runs about half a size larger than your non-dominant hand. If the ring is going on the right hand and you measured the left, you're already off.
Forgetting the knuckle. If your knuckle is significantly wider than the base of your finger, the ring needs to clear the knuckle to go on, then sit loose at the base. Size for the knuckle, not the base. Or get a ring with a wide band and a slight curve that locks in place.
Sizing for a thin band when you want a wide one. A wide band (4mm or more) fits tighter than a thin one at the same size. If you're shopping wedding bands and your engagement ring is a 6, you may want a 6.25 or 6.5 in the wider style.
Buying a surprise engagement ring without sizing first. If you cannot ask the recipient directly, borrow an existing ring she wears on the correct finger and bring it in. We can measure it on a mandrel in 30 seconds. The borrowed-ring method is the only reliable surprise-proof option.
What to do if the ring arrives and it's wrong
This is where buying from a local jeweller versus a faceless online store actually matters. At Vanhess, most simple resizes (a half size up or down, in 14K or 18K gold) take 3 to 5 business days at the bench. Eternity rings, channel-set bands, and rings with stones near the shank take 7 to 10 days because the work is more involved. We do all of it on site, so the ring never leaves Coquitlam.
If the size is more than two full sizes off, we sometimes recommend a remake instead of a resize, because aggressive resizing can weaken a thin band. We'll tell you which is the right call when we see the ring.
Key Takeaways
- The string method is unreliable because string stretches. GIA recommends a steel finger gauge instead.
- Measure three times across different days and use the largest result. Fingers change size with temperature and salt intake.
- Your dominant hand is about half a size larger than your non-dominant hand.
- Wide bands fit tighter than thin bands at the same numerical size. Account for the band width when ordering.
- If you can't measure in person, the most reliable backup is borrowing an existing ring the wearer already owns.
Frequently Asked Questions
What is the most accurate way to measure ring size at home?
The most accurate at-home method is a plastic adjustable ring sizer, available for around three dollars online. It mimics the steel finger gauges jewellers use in shop. Wrap-and-measure paper strips work in a pinch but should be repeated three times across different days, with the largest measurement chosen. The Gemological Institute of America warns against string-based methods because string stretches and gives inconsistent readings.
Why does GIA say not to use string for ring sizing?
String stretches in two directions, so the same finger can produce three different measurements with three different pulls. The result is usually a ring that's too tight, because people unconsciously pull string snug while measuring. GIA recommends a finger gauge or a jeweller's mandrel instead, both of which are rigid and can't stretch.
How long does it take to resize a ring at Vanhess?
At our Coquitlam shop, most simple resizes (a half size to one full size, in 14K or 18K gold) take 3 to 5 business days. Resizes involving channel-set stones, eternity bands, or significant size changes take 7 to 10 days because the work is more involved. We do all resizing on site, so your ring never leaves the shop.
Should I size for my finger when it's hot or cold?
Always size for the larger state. Fingers swell in heat, after salty meals, and during exercise. They shrink in cold weather and dehydration. A ring sized to a cold finger will be uncomfortable in summer, and in extreme cases will need to be cut off. A slightly loose ring in cold weather is the safer trade-off.
Is dominant hand bigger than non-dominant hand?
Yes, by about half a ring size on average. If you measure your left ring finger but plan to wear the ring on your right, add half a size. This is one of the most common reasons people receive a ring that doesn't quite fit.
Sources
- Gemological Institute of America — Ring Size Guide: Tips and Ring Size Chart
- Ring size standards reference, including ISO 8653:2016
Sourced April 2026. Sizing standards don't change often, but if you spot something off, let us know — we'd rather fix it than leave bad info up.
Visit Vanhess
If you're anywhere in the Tri-Cities, just come in. We'll size your finger on a steel mandrel in under a minute, no appointment needed, and we can do it for everyone in your household at the same time. We're at 2929 Barnet Highway, Unit 2424, Coquitlam, open Monday to Saturday. You can also reach us at (604) 653-6449. If you're already shopping, browse our full ring collection or our engagement rings.
