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UK Coin Identifier

Found a coin and not sure what it is? Answer four short questions, or measure a worn coin's diameter and weight, and we'll match it to our catalogue of 4,873+ British coins, with realised auction values on every match.

Measure your coin

Diameter is the distance straight across the face, in millimetres. A ruler works; calipers are better. Weight is optional but narrows things fast, so use kitchen or pocket scales if you have them.

Reference points: a 1p is 20.3mm and 3.56g; a 50p is 27.3mm and 8.0g; a £2 is 28.4mm and 12.0g. Pre-decimal? A big copper penny is 31mm and 9.4g, a half crown 32.3mm and 14.1g.

How the identifier works

The question path narrows the catalogue one attribute at a time: portrait (which fixes the monarch and reign), denomination, year, and finish. The measure path ranks every catalogued coin by how close its official diameter and weight sit to your measurements, which works even when the coin is worn smooth. Either way you typically end with one to three matches, each linking to a full coin page with realised auction prices, mintage figures, rarity scores and reference images. We don't use AI guesses: every result is a real coin in the catalogue.

Frequently asked

How accurate is this coin identifier?
It uses a structured decision tree against our 4,700+ catalogue of British coins. If you correctly identify the portrait, denomination and year, the tool will narrow to the exact coin or a small handful of variants. For ambiguous coins (e.g. mules, errors, patterns) the result page links to relevant guides.
What if I don't know the year?
The year is normally beneath the portrait on the obverse. If it has worn away you can usually guess the decade from the portrait style; pick a representative year and review the matches.
How do I identify a coin that is too worn to read?
Switch to the "Measure it" tab. Measure the diameter in millimetres with a ruler or calipers, weigh it in grams if you have scales, and note the shape. The identifier ranks every catalogued British coin by physical closeness, so even a smooth, dateless coin usually narrows to a handful of candidates.
How accurately do I need to measure?
The diameter search allows 1.2mm either way and weight allows 12%, so a household ruler and kitchen scales are fine. Calipers and 0.01g scales narrow the results further. Weigh the coin clean and dry; heavy wear can remove a few percent of the original weight.
Does this work for foreign or Roman coins?
No. This identifier is scoped to British circulation and commemorative coinage from medieval times to the present. For Roman, Anglo-Saxon hammered or other ancient coinage, the British Museum and the Portable Antiquities Scheme are the right starting points.
Is this a free service?
Yes, completely free with no account required. If you want to track the coins you find, free MyCoinage accounts let you save up to 25 coins to a personal collection.
What if my coin is fake?
Several common UK coins are widely counterfeited, most notably the Kew Gardens 50p and the £1 coin pre-2017. Once you have a match, our individual coin pages flag the common counterfeit tells and show genuine reference images.

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