How to Find Someone's Ring Size Secretly for a Christmas Gift
The easiest way to find someone's ring size secretly is to borrow a ring they already wear on the same finger, measure its inside diameter, and match it to a US ring size chart. If you can't borrow one, ask a close friend or family member, look for old jewelry receipts, or go half a size up rather than down.
That's the short version. The rest of this guide walks through each method step by step, gives you a size chart you can use with a ruler, and explains what to do when you truly have nothing to go on. It's written for anyone planning a ring as a Christmas surprise, a push present or a birthday gift, and who would rather not ruin the surprise by asking, "So, what size are your fingers?"
Why ring size matters more for a personalized gift
With a plain ring from a high street shop, a wrong size is annoying but fixable. You swap it. With an engraved ring it is different. A personalized birthstone name ring is made to order with one name and one birth month, so it can't go back on a shelf for someone else. That's why personalized pieces like this are final sale, and why it pays to spend ten quiet minutes on the size before you order.
The good news is that you don't need to be exact to the millimetre. You need to land in the right whole size. Most rings sold online, including ours, come in whole US sizes, so your job is to work out whether she's closer to a 6, 7, 8, 9 or 10.
Method 1: borrow a ring she already wears
This is the most accurate secret method, because you are measuring something that already fits. The trick is choosing the right ring.
Pick a ring from the right finger
Fingers are different sizes. A ring she wears on her index finger will be too big for her pinky and may be too small for her ring finger. Think about where your gift will be worn. A name ring for mom is often worn on the right hand ring finger or stacked on the middle finger, so borrow a ring from that finger if you can. Her dominant hand is usually slightly larger too.
Measure the inside diameter
Lay the ring flat on a ruler with millimetre markings. Measure straight across the inside of the band, edge to edge, not including the metal. Write the number down and put the ring back exactly where you found it. Then find the closest match in the chart below.
No ruler handy? Trace it
Put the ring on a piece of paper and trace around the inside with a sharp pencil. You can also press it gently into a bar of soap to leave a clean impression. Either way, you can measure later, with the ring safely back in her jewelry dish.
US ring size chart for sizes 6 to 10
Use this chart with either measurement. Inside diameter comes from a borrowed ring. Circumference comes from wrapping a paper strip around a finger, which is handy if you can get help from someone she won't suspect.
| US ring size | Inside diameter (mm) | Circumference (mm) | Good to know |
|---|---|---|---|
| 6 | 16.5 | 51.9 | Common for slimmer fingers and pinky or middle-finger stacking |
| 7 | 17.3 | 54.4 | One of the most frequently bought women's sizes |
| 8 | 18.1 | 57.0 | A safe choice if you are between 7 and 8 |
| 9 | 19.0 | 59.5 | Often right for index fingers or larger knuckles |
| 10 | 19.8 | 62.1 | Larger fingers, or a ring worn on the thumb side of the hand |
If your number falls between two sizes, go up to the larger one. A slightly loose ring can move to a different finger. A ring that won't pass the knuckle can't be worn at all.
Our engraved name ring with a birthstone color stone comes in exactly these five US sizes, 6 through 10, in gold tone, silver tone and rose gold tone.
Method 2: ask without asking
If you can't get your hands on a ring, you can still get the number. You just need a little help or a little creativity.
Recruit a sister, friend or daughter
The person she shops with probably knows her size, or can find out. A friend can try on her rings "just for fun" or suggest a trip past a jewelry counter together. Kids are surprisingly good at this too. A child playing dress-up with mom's rings is completely normal.
Check the paper trail
Look for old jewelry receipts, order confirmation emails, or the box from a ring she loves. Many jewelers print the size on the receipt or the tag. If she was ever sized for a wedding or engagement ring, that number is a strong starting point. Wedding sets are usually worn on the left hand, so the right hand may be a touch larger.
The paper strip trick while she sleeps
It sounds like a sitcom plot, but it works. Cut a thin strip of paper, wrap it gently around the base of her finger, and mark where it overlaps. Measure the length in millimetres and match it to the circumference column above. Use paper rather than string, because string stretches and gives a reading that runs large.
When you have to guess
Sometimes there is no ring to borrow and no one to ask. You can still make a sensible choice.
- Start from the middle. US women's sizes 6 and 7 are often cited as the most common, so a 7 is a reasonable default for an average build.
- Adjust for her hands. If her hands are long or her knuckles are prominent, lean toward an 8. If her fingers are very slim, a 6 is more likely.
- Think about recent changes. Fingers often swell in pregnancy and may take months to settle afterwards. If the ring is a gift for a new mom, half a size larger than her old size is kinder than one that pinches.
- Remember the weather. Fingers shrink a little in cold weather and swell in heat. A ring that fits snugly in December will feel tighter in July.
Band width matters as well. A wide band covers more of the finger and feels tighter than a narrow band in the same size. A dainty band about 2.5 to 3 mm wide, like the one on our name ring, generally fits true to size, so you don't need to adjust for it.
Choosing the finish, name and birth month
Once the size is settled, the fun part is quick. There are three choices to make.
Finish
Match the jewelry she already wears every day. If her watch and earrings are yellow, choose gold tone. If she wears cooler colors, silver tone. Rose gold tone sits nicely with both and is a safe pick if she mixes metals.
Name and stone
Each ring carries one engraved name and one birthstone color stone. For a mother's ring, that usually means a child's name with their birth month. For a grandma, it might be a grandchild. When you order, you type the name and birth month together in the Name & Birth Month box, for example "Emma - May".
One ring, or a stack
Because each ring holds one name, many families order one ring per child and let mom wear them as a stack. If she wants two names and two stones on a single band, the two birthstone ring may suit her better. For a quick reference, here are the stone colors by month on the name ring:
| Month | Stone color | Month | Stone color |
|---|---|---|---|
| January | Garnet red | July | Ruby red |
| February | Amethyst purple | August | Peridot green |
| March | Aquamarine blue | September | Sapphire blue |
| April | Clear | October | Pink tourmaline |
| May | Emerald green | November | Citrine yellow |
| June | Alexandrite purple | December | Blue topaz |
One small care note to pass on with the gift: the ring should come off before showering, swimming or exercise, and stay away from perfume and lotion.
No size at all? Gifts that skip the question
If every method fails and you don't want to gamble, choose a piece where size doesn't matter. You keep the same idea, names and birth months, without the risk.
- A name necklace with a birthstone carries one name and one month, much like the ring.
- An initial necklace with a birthstone is subtler, for someone who prefers a single letter to a full name.
- A family birth flower necklace with birthstones holds the whole family in one piece.
- A personalized heart birthstone bracelet or a heart initial birthstone bracelet works well for moms who already wear a wedding set and don't want another ring.
Some people give the necklace now and the ring later, once the size has been "accidentally" discovered.
Frequently asked questions
What is the most common ring size for women?
In the US, women's sizes 6 and 7 are the most often cited as common, with 7 a sensible middle choice. Averages only help so much, though. Height, hand shape, knuckle size and which finger the ring goes on all change the answer. If you have any clue at all, such as a borrowed ring or an old receipt, trust that over the average.
Should I size up or down if I'm not sure?
Size up. A ring that is half a size too large can be moved to a slightly bigger finger, or worn on a different hand, and it will feel comfortable on warm days. A ring that is too small may not pass the knuckle at all. With a personalized ring that can't be exchanged, the larger size is the safer gamble.
Can I measure ring size with a piece of string?
You can, but paper is better. String stretches as you pull it, so the reading tends to run large. Cut a thin strip of paper instead, wrap it snugly around the base of the finger, and mark where it overlaps. Measure that length in millimetres and match it to the circumference column in a ring size chart.
Does ring size change during or after pregnancy?
Often, yes. Many women find their fingers swell during pregnancy, and it can take several months after the birth for them to settle back. If you're buying a ring for a new mom, choose half a size larger than her usual size, or pick a necklace or bracelet and save the ring for later in the year.
Which finger is a mother's ring worn on?
There's no rule. Many moms wear a name or birthstone ring on the right hand ring finger, so it doesn't compete with a wedding set. Others stack it with the wedding band, or wear it on the middle or index finger. Find out which finger she'd likely choose, and measure a ring from that same finger.
Getting the gift ready before Christmas
Pick your method this week, measure while the house is quiet, and write the number somewhere she won't look. Then check the spelling of every name twice, because personalized rings are made to order and can't be changed once they're engraved. Delivery times are listed in the Shipping tab on each product page, so check them early in the season.
When you're ready, choose a birthstone name ring in her size, from $20.73, or browse the full Engraved Treasures jewelry collection for necklaces and bracelets that skip the sizing question entirely.