Remember the printable ring size chart is not a professional measurement and should be used more as a guide. A meeting with one of our in-store experts is the best way to ensure you have the exact ring size.

If the worst happens and you select a ring in the incorrect size, Goldsmiths' expert jewellery crafts people can resize it for you.

The only exception to this service is with eternity and some other gemstone rings: these cannot be resized due to the setting, although they can be exchanged for a different size.

Aside from the where, what, why and how of your surprise proposal, getting a ring to fit your intended's finger ahead of time can be a tricky prospect.

The following are a few tips for secretly obtaining your partner's ring size, gleaned from the collective knowledge of our experienced team here at Goldsmiths. Once you have discovered your partner's size, you will be better able to peruse our extensive collection of diamond solitaire and gem-set engagement rings in a full choice of precious metals.

The simplest way to find your partner's ring size is to 'borrow' a ring they already wear. As engagement and wedding rings are typically worn on the third finger of the left hand, it's perhaps unlikely that that finger is already adorned. Simply choose a ring usually worn on the middle finger instead, and be prepared to go down a size or two for the right fit.

Once you have managed to source an appropriate ring, head to your local Goldsmiths showroom, where our experts will be on hand to size match it for you.

If your partner is likely to notice the disappearance of a ring, then carefully draw around the inside of it on a piece of paper, for a more approximate ring size guide. You can then bring this piece of paper into one of our UK stores, where we will be able to get a good estimate of sizing.

If your partner is a heavy sleeper, you could even try using our downloadable Ring Size Guide in the middle of the night for good ring size estimate!

Your partner's friends and family are a great source of help if you're still wondering how to measure their ring size. They may be better placed to get the information without raising suspicion, so if you can enlist their help, take advantage of it. Just be sure they will keep your secret if you want the proposal to be a surprise.

If in doubt, choose a slightly larger ring size. It is easier to make a larger ring smaller without damaging the integrity of the piece, and it will also help to salvage the romance of the moment if the ring is a little too large than if it simply won't go onto your beloved's finger.

Rings that have a deep band width will need to be slightly larger than your normal rings so consider this when checking your size.

If you find the ring you've bought from us is too big or small, just take it along to one of our showrooms. We'll either re-size or exchange it, to make sure you always get the perfect fit.

Once you have the ring size, our team can provide you with everything you need to know about which ring style will work well for your partner. From shape, to diamond cut, and metal type – we are the engagement ring experts with almost 240 years of quality, tradition, and craftsmanship behind us.

Additionally, Goldsmiths are proud to hand-make wedding rings and engagement rings in the UK. We'll talk you through different stones, colours of metals, engravings and shapes to ensure you find exactly the ring you're looking for.

If you prefer to go ring shopping together, then bring your partner into your local showroom. We will provide champagne and special treatment. Spend some time looking at engagement rings together, choosing the one that best reflects your lifestyle, relationship and aesthetic preferences without having to worry about knowing how to measure their ring size.