If you paid attention to De Beers' advertising in the 1980s, you'd have been told that two months' salary was a small price to pay for something that lasts forever. And then somewhere in the last forty years, two months turned into three months, and now the so-called three month rule is almost ubiquitous.

What does that mean in practice? In the UK, the median salary is about £33k (or £42k in London). That would make three months' salary roughly £6,462 (or £8,145 in London) – assuming you're counting your salary after tax, not before. Big amounts to spend on something very small.

But how much are couples really forking out? We asked Twitter to guess the average, and most people were pretty close: typical guesses ranged from £500 to £5,000, with most hovering around £2k.

Most research suggests that the real answer (at least as of 2020) is about £1,865. That's less than one month's salary, and less than half of what the average Brit spends on going out to eat in a year.

But it's also a significant amount to spend as a lump sum, particularly during the cost-of-living crisis – and given that precious stones are now easily synthesised for trivially small amounts of money, are we throwing away cash for no reason? Let's find out.

Raw materials

Today, it costs about $300 per carat to create a lab-grown diamond. Natural diamonds, meanwhile can cost many times as much to extract, with each carat requiring about 250 tonnes of earth to be shifted. Many of those costs are included in the price of the diamond; others – such as the pollution, harm to wildlife, and destruction of local communities – are not. Lab gems are also energy-intensive to create, but produce about half as much CO2 as their mined counterparts.

Then there's the metal. Silver, gold, and platinum are the most common choices, with silver costing the least and gold (usually) the most. An ounce (28g) of silver would set you back approximately £18 if you bought it on an exchange, but you'll be lucky to find a ring weighing a fraction of that for less than £50.

This is because a significant amount of an engagement ring's cost base comes from the jeweller's work, but also – crucially – marketing and other overheads. This is why rings, including those featuring natural gemstones, have such low resale value: the materials themselves are worth a relatively modest proportion of the overall cost. As a rule, jewellery is not a sensible investment.

Types of seller

If you're lucky and have inherited a ring from family, all this deliberation can be avoided, provided your partner likes the style of vintage jewellery. You can also buy vintage rings second-hand, and many high street jewellers offer second-hand rings at much more reasonable prices than their new stock.

Independent sellers typically have fewer overheads than high street or high-end retailers, and are likely to charge less for materials and their time – which means customisation becomes more affordable, so you can design something unique and tailored to your partner's tastes.

Some couples choose to forge their own rings, making truly individual rings for each other or themselves and sharing an activity at the same time. This does have limitations: the rings won't have jewels in, and are likely to be heavier and less delicate than traditional engagement or wedding rings.

Other considerations

If you're spending any non-trivial amount on a ring, insurance is a dull but essential consideration. Knowing that you're covered if the ring falls into a drain or gets lost is invaluable.

Some couples even opt to buy two engagement rings: one affordable ring to wear every day or when travelling, which can get lost without causing undue stress, and one 'real' ring made with more expensive materials or craftsmanship.

If you're the one planning to propose, you'll also want to consider whether you know your partner's taste well enough to choose something on their behalf, or whether you're prepared to lose the element of surprise in exchange for getting it just right. Running everything past their closest friends is a good way to play it safe here.

Finally, make sure you know their ring size (hint: there's more to it than small, medium, or large).

If you don't, ask a friend whose fingers are a similar size, or measure one of your partner's existing rings – or take it to a jeweller to get it sized – when they're not paying attention.

Good luck!

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