How to Figure Out Ring Size Secretly
Updated 6 November 2026
Keeping a proposal a surprise gets awkward when you need to know which ring size to order. The most useful clue is a ring your partner already wears comfortably on the intended finger, on the correct hand. Someone who knows their current size may be able to help, too.
Treat either as a starting point. Before ordering, tell the jeweller where the size came from and check the resizing options for your chosen design. You can keep the proposal itself a surprise while being open about wanting a ring that fits.
Start with a ring that fits the right finger
If borrowing a ring your partner wears is an option, take the actual ring to a jeweller for measurement. First, be clear about which hand and finger it fits, and whether it feels comfortable or is already a little loose or tight. An old ring at the back of a jewellery box may tell you very little about their size today.
There is no dependable rule for converting a middle-finger size into a ring-finger size, or for adjusting a measurement from one hand to the other. Subtracting a couple of sizes is a guess. If you only have a ring worn on a different finger, say so; a jeweller can measure that ring without being able to confirm the size you need.
Our Manchester and London Marylebone showrooms can help with measuring an existing ring, as can a local jeweller. Arrange an appointment and explain what you have available before visiting.
If you have your eye on a stunning solitaire or a moissanite engagement ring, mention the design as well as the size. The width and shape of the band matter when discussing how it will fit.
Ask someone who already knows
A close friend or family member might know your partner’s size from a recent jewellery purchase or a conversation they have already had. Ask how they know, rather than accepting a letter or number without any context. Check the hand, finger and sizing system, too: a UK letter and a US number are different ways of recording size.
If nobody has reliable information, a simple conversation may save a lot of uncertainty. You could find out your sizes together well before the proposal, keeping the date and ring choice to yourself.
We offer a free ring sizer for measuring at home; check the current ordering and delivery details before requesting one. Use it with your partner, following the instructions and checking that it feels comfortable. Trying to measure a finger without someone noticing is unlikely to give you a useful fit check.
Know the limits of photos, tracings and guesses
A photograph can help you discuss a ring’s appearance, but it cannot establish your partner’s ring size. Hand size, clothing size and an “average” ring size are poor substitutes for a measurement of the intended finger.
A pencil outline also leaves room for error: the thickness of the line and the angle of the pencil can change the measurement. Prefer the actual ring over a tracing, and leave soap impressions out of the process. String and paper strips can stretch, curl or sit differently from a solid band, and measuring only the base of the finger misses the question of getting the ring over the knuckle.
Friends may be more useful for finding out what your partner likes. Knowing they have admired a pavé diamond ring, a sapphire ring from the gemstone collection or a trilogy design can narrow the search. Keep that style advice separate from the question of size.
Have the fit checked for the ring you choose
A ring needs to pass over the knuckle and sit comfortably at the base of the finger. It should not pinch or feel at risk of slipping off. The same nominal size can feel different in a broad band and a narrow one, or when the inside of the band has a different profile. Fingers can also change size with temperature and time of day.
GIA’s ring-sizing guidance explains why different band designs need different measuring techniques. A professional fitting gives the wearer a chance to compare sizes and describe how each one feels.
You can book an in-person appointment to discuss the ring and fitting, or a virtual consultation to talk through the options from home. A video call is useful for planning; confirming how a ring feels still requires the wearer to try an appropriate sizer or ring.
Check resizing before you order
Resizing can help when the fit needs adjusting, but it is not possible for every ring or every size change. Rings with stones around the whole band, ornate details and some bespoke designs can have restrictions. Do not assume that ordering a larger size will always make things easier later.
Our current service terms provide for one free resize within a year of receiving the ring, subject to the design and the change required. A replacement mount or some custom work can involve additional costs. Ask the team to confirm eligibility, any charges and the expected timescale for the particular ring before you buy.
If you are planning around Black Friday, our Black Friday Promise explains our approach to year-round pricing. Resizing eligibility and timing are covered separately, so check the service terms for your order.
If you still don’t know the size
You don’t have to turn a guess into an order. Speak to the team about the information you have, or involve your partner in a fitting while keeping the rest of your plans private. The surprise can be where and when you ask.
As you compare engagement rings, make a note of the designs your partner would enjoy wearing and ask about fit alongside style. A little clarity before ordering gives you one less thing to worry about on the day.