Planning a surprise proposal means getting the ring right without giving the game away. The good news: you don't need her exact size to order with confidence. Here are the most reliable ways to find it discreetly, plus a US and UK size chart.
1. Borrow a ring she already wears
This is the most accurate method. Choose a ring she wears on her ring finger (left hand in the US and UK). If that's not possible, a ring from her right ring finger is a good guide, though dominant hands are often slightly larger. Then either:
- measure the inside diameter in millimeters with a ruler and use the chart below, or
- press it into a bar of soap or trace the inside circle on paper, and return the ring before she notices.
2. Ask a friend or family member
Her best friend, sister or mother may already know her size, or can find out naturally ("Let's try on rings for fun!").
3. Take her ring "for cleaning"
Offer to have one of her rings cleaned or repaired, and measure it while you have it.
4. Compare against your own finger
Slide one of her rings onto your finger and mark where it stops. It's not exact, but it narrows it down.
5. Use the average as a starting point
If you truly have nothing to go on, many women's ring sizes fall around US 6 to 7 (UK L½ to N½). It's a reasonable starting point, but always use real information if you can get it.
6. If in doubt, size up slightly
A ring that's a little big can still be worn safely until it's resized; one that's too small can't be worn at all. LUXEIGA includes one free resize within 60 days of delivery on designs that can be resized.
Ring size conversion chart
| US size | UK size | Inside diameter |
|---|---|---|
| 4 | H½ | 14.9 mm |
| 4.5 | I½ | 15.3 mm |
| 5 | J½ | 15.7 mm |
| 5.5 | K½ | 16.1 mm |
| 6 | L½ | 16.5 mm |
| 6.5 | M½ | 16.9 mm |
| 7 | N½ | 17.3 mm |
| 7.5 | O½ | 17.7 mm |
| 8 | P½ | 18.1 mm |
| 8.5 | Q½ | 18.5 mm |
| 9 | R½ | 19.0 mm |
Sizes are approximate. Measure the inside of a ring that fits well, from edge to edge across the widest point.
Good to know
- Wide bands fit tighter. For bands wider than about 4 mm, consider half a size up.
- Fingers change size. They're smaller when cold and larger when warm, so avoid measuring first thing in the morning or straight after exercise.
- Full eternity rings can't be resized, so it's worth confirming the size before ordering one.
Still unsure?
Our specialists help with this every day. Book a free video consultation and we'll help you work out her size discreetly, or design her ring now and choose your best estimate.