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How is gold weighed?

Written by Vintage Cash Cow | Jun 17, 2026 2:01:07 PM

If you've ever wondered what actually happens when someone weighs a gold ring or chain, the short answer is that it comes down to precision scales, the right units, and a purity check alongside the weight itself. Weight on its own only tells part of the story. To work out what a piece of gold jewellery is genuinely made of, you need to know both how heavy it is and how pure it is.

Here's how the process actually works, and why both figures matter when it comes to valuing gold.

The scales used to weigh gold

Gold is weighed using calibrated precision scales, not standard kitchen or bathroom scales. These are digital instruments designed to measure very small amounts accurately, often down to a tenth of a gram or finer. Jewellers, valuers and refiners rely on this level of accuracy because even a small difference in weight can affect the value of a piece, particularly with higher purity gold.

These scales are checked and calibrated regularly to make sure readings stay accurate over time. This matters because gold is often weighed in small quantities, sometimes just a few grams for a ring or pair of earrings, so any drift in the scale's accuracy could affect the result.

What units is gold weighed in?

Several units are used for weighing gold, depending on the context. The most common ones you're likely to come across are:

  • Grams (g): the standard unit used for most jewellery in the UK, including rings, chains, bracelets and earrings
  • Troy ounces (oz t): used internationally in the bullion and investment market, with one troy ounce equal to about 31.1 grams
  • Pennyweight (dwt): an older imperial unit still occasionally used in the antique and jewellery trade
  • Carat: often confused with weight, but this actually measures purity, not how heavy a piece is

That last point trips a lot of people up. A nine carat ring and a 22 carat ring of the same weight will contain very different amounts of actual gold, because carat tells you the proportion of pure gold in the metal, not the size or weight of the item.

Weight is only half the story

Once an item has been weighed, the next step is working out how pure the gold actually is. This is usually done through one or more of the following methods:

  • Acid testing, where a small amount of acid is applied to a discreet area to see how the metal reacts
  • XRF (X-ray fluorescence) testing, a non-destructive method that reads the metal's composition using x-rays
  • Hallmark inspection, checking for stamps such as 375, 585, 750 or 999, which correspond to 9ct, 14ct, 18ct and 24ct gold

This is an important step, because two items of identical weight can have very different gold content depending on their purity. A 22 carat bracelet weighing ten grams contains considerably more pure gold than a nine carat bracelet of the same weight.

How weight and purity combine to determine value

Once both figures are known, the weight and purity are considered together against the current market price of gold. The global gold price moves daily and is widely tracked through international benchmarks, including those set by the London Bullion Market Association, which many in the trade use as a reference point.

This is also why two seemingly similar pieces can be valued quite differently. A heavier item in a lower carat might be worth less than a smaller, higher purity piece once weight and purity are both factored in.

It's worth noting that condition doesn't change this calculation much. A dented ring or a tangled, broken chain still contains the same weight of gold as it did before it was damaged, so items like these are still assessed on weight and purity rather than appearance.

How this applies when you sell jewellery

When you choose to sell gold with us, this is exactly the process our specialists follow. Rather than offering an estimate on the spot, every item sent to us is individually weighed and tested by our in-house team before a single, considered offer is put together for your collection.


This approach takes a little longer than an on-the-spot guess, but it means every piece is properly weighed and tested rather than valued by eye. With more than 100 in-house specialists and over 33,000 Trustpilot reviews, we aim to make the process as transparent and straightforward as possible, whatever condition your jewellery is in.

If you'd like to find out more about what we look at when assessing items, our How It Works page walks through the full process, and our What We Buy page covers the full range of items we accept, including damaged or odd pieces.

Whether you've got a single drawer of jewellery or a larger collection, requesting a free postage pack or booking a home collection is a simple way to find out what's there, with no obligation to accept the offer you're given.