Your fingers are smaller at 7 a.m. than at 7 p.m. They shrink in the cold, swell after a salty dinner and puff up on a long flight. So when an at-home ring size comes out wrong, the method usually isn't the problem. The timing is.
Get the timing right and you only need a ruler and about five minutes. Here's how we'd do it.
First, pick the right moment
Measure at the end of the day, when your hands are warm and your fingers are at their fullest. Skip right after a workout, a long flight, a hot shower or a salty meal, all of which make fingers swell for a while. And don't measure with cold hands. Cold fingers can read up to half a size small, which is how a ring sized on a winter morning ends up stuck in July.
If you can, measure twice on different days. Two readings that agree beat one careful one.
Method 1: Measure a ring that already fits
This is the most reliable way to do it at home. Pick a ring you wear on the same finger, ideally a plain, thin band. Lay it flat and measure straight across the inside, from inner edge to inner edge, in millimeters. Match that number to the chart below.
Two warnings. Wide bands fit a little tighter than thin ones in the same size, so a wide ring will point you slightly small. And rings with big stones sit crooked when laid flat, which throws off the reading.
Method 2: A strip of paper
No ring to borrow? Cut a thin strip of paper (paper is better than string, which stretches). Wrap it around the base of your finger, snug but loose enough to slide over the knuckle, and mark where the end overlaps. Lay it flat against a ruler and measure to the mark in millimeters. That's your circumference.
Do it three times. If the numbers disagree, go with the one in the middle.
The ring that fits perfectly in the morning is the one that's stuck by dinner.
The chart
Standard US sizes, measured on the inside of the ring. Our ring size chart has the full guide.
| US size | Inside diameter | Inside circumference |
|---|---|---|
| 4 | 14.9 mm | 46.8 mm |
| 5 | 15.7 mm | 49.3 mm |
| 6 | 16.5 mm | 51.9 mm |
| 7 | 17.3 mm | 54.4 mm |
| 8 | 18.1 mm | 57.0 mm |
| 9 | 19.0 mm | 59.5 mm |
| 10 | 19.8 mm | 62.1 mm |
| 11 | 20.6 mm | 64.6 mm |
Each full size adds about 0.8 mm across, or about 2.5 mm around.
Watch the knuckle
If your knuckle is noticeably wider than the base of your finger, measure both. A ring sized to the base won't get over the knuckle, and a ring sized to the knuckle will spin. Choose the size that slides over your knuckle with a little resistance and then sits comfortably at the base.
Between sizes? Go up
When you land between two sizes, take the larger one. The same goes for chunkier bands, which cover more of your finger and feel tighter than a thin band in the same size. A ring that's a touch roomy gets worn. A ring that's a touch tight gets left on the dresser.
Every finger is its own size
Don't measure your ring finger and buy for your index finger. Index fingers usually run larger than ring fingers, and pinkies run a lot smaller, often by a few sizes. Your dominant hand tends to be a little bigger too. Measure the exact finger, on the exact hand, you plan to wear it on.
The fit test
When the ring arrives, a good fit slides over your knuckle with a bit of push, doesn't spin on its own, and doesn't leave a dent when you take it off. If it fails, our size exchanges are free within 30 days of delivery.
Most of our rings come in sizes 4 through 11, so whatever your fingers measure, the fun styles are on the table.
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Starlight Ring
Chalice Ring
Mini Me RingQuestions about measuring your ring size
How can I find my ring size without a ring sizer?
Measure the inside diameter of a ring that already fits the same finger, or wrap a thin strip of paper around the base of your finger, mark the overlap and measure it in millimeters. Then match the number to a ring size chart.
What time of day should I measure my ring size?
At the end of the day, with warm hands. Fingers are smaller in the morning and in the cold, and they swell after exercise, flights and salty meals.
Should I size up or down if I'm between sizes?
Size up, especially for wider bands, which fit tighter than thin bands in the same size.
Is my ring size the same on both hands?
Not always. Your dominant hand is often slightly larger, so measure the hand you'll actually wear the ring on.
What ring sizes does Oomiay carry?
Most Oomiay rings come in US sizes 4 through 11. Availability for each size is shown on the product page.
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Your turn. Which finger was hardest to size, and what size did it come out? Tell us in the comments.