Find Your Ring Size
Enter your measurement below to get an instant ring size recommendation.
How to use this ring size calculator
This calculator estimates your ring size based on either your finger circumference or your ring’s inside diameter. If you already own a ring that fits well, measuring its inside diameter is often the easiest path. If not, you can measure your finger directly with a strip of paper or a flexible measuring tape.
- Choose whether your input is circumference or diameter.
- Select the unit (mm or inches).
- Pick your preferred fit style.
- Click Calculate Ring Size to see your recommendation.
How to measure ring size at home
Method 1: Measure finger circumference
Wrap a strip of paper around the base of your finger. Mark the spot where the paper overlaps, then measure that length with a ruler. That measurement is your finger circumference.
- Measure at the end of the day when fingers are slightly larger.
- Avoid measuring when your hands are very cold.
- Measure 2–3 times and use the average value.
Method 2: Measure an existing ring
Place the ring on a ruler and measure the inside edge from one side to the other. Do not include the metal thickness—only the open inner circle.
- Use millimeters for better precision.
- If between sizes, go up for wider bands.
Understanding the result
Your result includes:
- US size (common in the United States)
- UK size (letter-based scale)
- EU size (roughly inner circumference in mm)
The calculator also gives neighboring sizes so you can choose up or down depending on your band width and comfort preference.
Quick reference chart (approximate)
| US Size | UK Size | Diameter (mm) | Circumference (mm) |
|---|---|---|---|
| 6 | L 1/2 | 16.5 | 51.9 |
| 7 | N 1/2 | 17.3 | 54.4 |
| 8 | P 1/2 | 18.1 | 57.0 |
| 9 | R 1/2 | 18.9 | 59.5 |
| 10 | T 1/2 | 19.8 | 62.1 |
Tips for getting the best ring fit
1) Consider band width
Wide bands feel tighter than thin bands. If your ring is wider than about 6 mm, many jewelers recommend going up a half size.
2) Think about knuckle size
If your knuckle is significantly larger than the base of your finger, choose a size that can pass over the knuckle while still feeling secure.
3) Account for temperature and time of day
Heat can cause mild swelling, while cold can shrink fingers. Mid-to-late day measurements usually produce more realistic sizing.
Frequently asked questions
Is this calculator accurate?
It provides a strong estimate using standard conversion data. For high-value purchases (like engagement or custom rings), confirm with a professional jeweler.
What if I am between sizes?
If you prefer comfort or wear wider bands, size up. If you prefer a snug fit and wear narrow bands, sizing down can work.
Can rings be resized later?
Many rings can be resized, but materials and stone settings matter. Eternity bands and certain metals may have limited resizing options.