Ring size is the one detail that can turn a perfect proposal into a jeweller's appointment. The good news: you can find the size accurately at home — even secretly — with tools you already own. Here are the three methods that work, the mistakes that skew results, and what to do when you simply cannot measure.
Method 1: Measure a ring she already wears (best for surprises)
Borrow a ring she wears on the ring finger — not another finger, sizes differ noticeably between fingers and hands. Lay it on a ruler and measure the inside diameter in millimetres, edge to edge at the widest point. Then read the size from the table below.
No time to measure? Press the ring gently into a bar of soap and photograph the imprint next to a coin for scale, or trace the inner circle on paper several times and take the average.
Method 2: String or paper strip
Wrap a thin strip of paper (or non-stretch string) around the base of the finger, mark where it overlaps, and measure the length in millimetres — that is the circumference, which is exactly what EU sizes express. Measure in the evening, when fingers are their true size, and check the strip slides back over the knuckle with light resistance.
Method 3: Printable ring sizer
Our ring size guide includes a complete conversion chart and detailed instructions for all three methods. Print at 100 % scale (verify with the credit-card check) and match a ring against the printed circles.
Size conversion chart
| Inner diameter (mm) | EU size (circumference) | US | UK |
|---|---|---|---|
| 15.3 | 48 | 4.5 | I½ |
| 15.9 | 50 | 5.25 | K |
| 16.5 | 52 | 6 | L½ |
| 17.2 | 54 | 6.75 | N |
| 17.8 | 56 | 7.5 | O½ |
| 18.5 | 58 | 8.25 | Q |
| 19.1 | 60 | 9 | R½ |
The mistakes that skew measurements
Measuring in the morning or after cold. Fingers are smallest when cold and largest in the evening and summer — measure in the evening at room temperature.
Ignoring the knuckle. If the knuckle is clearly wider than the finger base, size for a point between the two — the ring must pass the knuckle but not spin at the base.
Wide bands. Bands over 6 mm wear tighter; go up half a size.
Measuring the wrong hand. Left and right ring fingers often differ by up to half a size. Measure the hand that will wear the ring.
Proposing and can't measure at all?
EU 53–54 is the statistically safest choice for women in Europe — slightly large beats too small, because a loose ring still goes on the finger for the photo. And crucially: most gold rings can be resized by one to two sizes. A proposal needs a ring, not a perfect fit. If the size isn't right afterwards, contact us and we will arrange the adjustment.
Frequently asked questions
How do I secretly find out my partner's ring size?
Borrow a ring she wears on the ring finger and measure its inside diameter against a ruler, or press it into soap and photograph the imprint with a coin for scale. Asking her friends or family also works more often than people expect.
What is the most common women's ring size?
EU 52–54 (US 6–6.75) covers the majority of European women, which makes EU 53–54 the safest blind choice for a surprise proposal.
When is the best time to measure a finger?
Evening, at room temperature. Fingers are smaller in the morning and in cold weather, larger in heat — evening measurement reflects real wearing conditions.
Can an engagement ring be resized?
Most gold rings can be adjusted one to two sizes either way. Eternity bands with stones all the way around are the main exception.
Should a wide ring be a larger size?
Yes — bands wider than about 6 mm sit tighter on the finger, so order half a size up.
Full charts and printable tools: ring size guide. Ready to choose? Browse engagement rings.