Your Guide to Engagement Rings

How much should you spend? The old "three months’ salary" advice may be a useful starting point, but it’s not a hard-and-fast rule. You can spend less and still find a terrific ring, or you can spend more and splurge on size or quality. The only "correct" amount to spend is the amount that fits your budget. With our enormous inventory, Amazon can help you find a beautiful ring at any price point.

The best way to find out what she likes is to ask her. Better yet, look at rings together. If you want the ring to be a total surprise, though, you’ll need to do a little sleuthing. Pay close attention to her style. Check out the jewellery she wears. Is it traditional? Romantic? Modern? Practical? Does she like showier pieces, or more subtle styles? What color of metal does she usually wear? White or yellow?

Don’t be afraid to enlist her friends and relatives to help. Ask her mother, her sister, or her best friend for advice (but first, make sure they can keep a secret).

The diamond you choose will be mounted in a ring, which is called the setting. That setting can be simple, or elaborate. It can hold the diamond flush with the band, or raise it high above it. It can highlight the diamond in a simple way, or it can shimmer with accent stones or fancy metalwork. Again, knowing her style will help you choose the right setting. Looking for something tried-and-true? Some of the most popular and classic diamond settings are the solitaire, the two or three stone, and the channel setting.

Consider her hand size when you choose the setting. A broader band will balance long, slender fingers, while something more petite will complement a smaller hand. For a flattering result, look for a diamond and setting that are proportionate to her ring size.

When you choose the setting, you’ll also need to choose the metal: White gold or yellow? Fourteen carat? Eighteen carat? Or platinum? See our Precious Metals Guide for help.

We're talking overall geometry of the diamond here. By far, the most preferred diamond shape is round-brilliant. With its 360 degree symmetry, it gives off the most sparkle. Princess shapes are the second most popular choice, with their clean square lines, modern look, and beautiful sparkle. Other choices include the regal-looking marquise (which has the advantage of lengthening the finger), and the classic emerald cut. The oval diamond is an elongated variation of the popular round brilliant, while the asscher diamond resembles an emerald cut, but with a squared shape and unique blocked corners. Other fancy shapes, such as pear, heart, and cushion, round out the list of possibilities.

Carat, Cut, Colour, and Clarity. These are the factors that determine the value of a diamond. See our Diamond Learning Guide for a crash course in what they mean and why they matter.

You can start by just asking her. If she doesn’t know, download and print Amazon.co.uk’s ring size chart, and use that to find out.

Keeping the ring a secret? Then you’ll have to get crafty. Secretly "borrow" one of her rings (making sure it’s one that fits the intended finger) and compare it to the size chart, or you can have a jeweller size it. Slip it back before she notices.

If you can’t sneak her ring away, try this: slip it on your own finger, as far down as it will comfortably go, and mark the line with a pen. A jeweller can then use that mark to measure and determine her ring size.

When in doubt, err on the slightly bigger side. It’s easier to have a ring sized down than up.

Ideally allow yourself plenty of time to make your purchase. That gives you time to learn about diamond engagement rings, consider your choices, and make an informed decision. That said, make sure you enjoy the shopping process as much as possible and put a smile on her face.