Gold sovereign weight and specifications

A full gold sovereign weighs 7.98805 g. It is struck in 22 carat gold and contains 7.32238 g of fine gold, which is 0.235420 troy ounces. The weight and the fineness have not changed since the first modern sovereign was struck in 1817, and the gold sovereign weight has been fixed by statute ever since.

The coin measures 22.05 mm across. That figure is not as old as the weight. The first sovereigns, struck from 1817 to 1820 under George III, were 21.0 mm; the 22.05 mm diameter dates from the recoinage under George IV.

Below are the specifications for every coin in the sovereign family, the statutory weights set out in the Coinage Act 1971, and the arithmetic behind each number so you can check it rather than take our word for it.

Sovereign specifications at a glance

Every coin in the family is struck in 22 carat gold: eleven parts fine gold to one part alloy. Expressed as a millesimal fineness that is 11/12, or 916.666 recurring, normally given as 916.7. You will also see it truncated to 916.66 and rounded to 917.

A few notes on the numbers, because sources disagree and it is usually a rounding question rather than a factual one.

• You will see the full sovereign quoted as 7.98805 g, 7.988 g, 7.99 g, 7.98 g and simply 8 g. The statutory figure is 7.98805 g. Anything shorter is a rounding of it.
• The gross weight of a sovereign is 0.256822 troy ounces. The figure that matters for valuation is the fine gold weight, 0.235420 troy ounces.
• The gramme column is quoted from Schedule 1 of the Coinage Act 1971 for the four statutory denominations, and from The Royal Mint for the quarter sovereign. The troy ounce column is calculated from exact multiples of the sovereign. That is why the final digit of the two columns does not always agree: they are rounded from different starting points, not describing different coins.
• The Royal Mint publishes a maximum thickness for the sovereign. We have not been able to confirm a published maximum for the other four denominations against The Royal Mint's own specification, so those cells are left open rather than filled with a figure we cannot source. There are derived average thicknesses for the whole family in the thickness section below, clearly labelled as ours.

Why a sovereign weighs 7.98805 grams

The weight is not a design decision. It is an answer to an arithmetic question asked in 1816 and never asked again.

The Great Recoinage of 1816 fixed the mint price of standard gold, meaning 22 carat gold, at 3 pounds 17 shillings and 10.5 pence per troy ounce, or 46 pounds 14 shillings and 6 pence per troy pound. Since a sovereign is by definition one pound sterling, the weight of the coin follows directly.

1. 46 pounds 14 shillings and 6 pence expressed as a decimal is 46.725. So one troy pound of standard gold was coined into 46.725 sovereigns.
2. A troy pound is 5,760 grains. 5,760 divided by 46.725 gives 123.27448 grains per sovereign.
3. A troy grain is 0.06479891 g exactly. 123.27448 multiplied by 0.06479891 gives 7.98805 g.

The fine gold content follows from the 22 carat standard, which is eleven twelfths gold.

1. 123.27448 multiplied by 11 and divided by 12 gives 113.00161 grains of fine gold.
2. A troy ounce is 480 grains. 113.00161 divided by 480 gives 0.235420 troy ounces.
3. 113.00161 multiplied by 0.06479891 gives 7.32238 g.

The mint price and the coin are the same statement

The 1816 mint price of 3 pounds 17 shillings and 10.5 pence per ounce was for standard 22 carat gold. In decimal that is 3.89375, and 3.89375 is also the number of sovereigns that weigh one troy ounce on the scale.

Convert the same price to fine gold by multiplying by 12 over 11 and it becomes 4.2477 per troy ounce. That is also the number of sovereigns needed to hold one troy ounce of fine gold. The two match because a sovereign is, by construction, one pound of gold at the 1816 price. The coin and the price are the same statement written two ways.

If you want the wider history of the coin rather than the metrology, our gold sovereign guide covers what a sovereign is and how the design has changed.

How the other denominations are derived

Weight scales exactly. Diameter does not. This catches people out.

Weight is a clean multiple

Each denomination is an exact multiple of the sovereign in grains, and the statutory table is that multiple rounded to five decimal places. The Act's gramme column truncates in two rows rather than rounding to nearest: an exact half is 3.994026 g and the Act gives 3.99402 g, and an exact five times is 39.940259 g and the Act gives 39.94025 g. Those are differences of a hundred thousandth of a gramme, a presentation choice rather than a difference between coins.

The quarter sovereign is the one genuine exception. An exact quarter is 1.99701 g and The Royal Mint publishes 1.99700 g. The quarter is also a modern coin, introduced in 2009, which is why it does not appear in the Coinage Act 1971 table further down. Its specification is set by Royal Proclamation under the Act rather than listed in Schedule 1.

Diameter is not a clean multiple

If the coins were the same shape scaled up and down, diameter would rise with the cube root of weight. It does not.

• A half sovereign at half the weight would be 17.50 mm across on pure geometric scaling. It is actually 19.30 mm.
• A quarter sovereign would be 13.89 mm. It is actually 13.50 mm.
• A five pound coin at five times the weight would be 37.70 mm across. It is actually 36.02 mm.

The reason is practical. Coins have to strike cleanly and stack sensibly, so mints keep them within a workable band of thickness. The fractional coins end up relatively wide and thin; the larger coins end up relatively narrow and thick. A quarter sovereign is not a miniature sovereign, it is a different shape of coin with a quarter of the gold in it.

For values across the smaller denominations, see our guide to half sovereign value.

The legal specification: standard weight, remedy and least current weight

The sovereign is not just a bullion product, it is UK legal tender, and its specification is set out in statute. Schedule 1 of the Coinage Act 1971 gives three weights for each gold denomination.

• Standard weight. What the coin is supposed to weigh.
• Remedy allowance. The permitted deviation at striking. Producing millions of coins to an absolute figure is not possible, so the Act builds in a tolerance.
• Least current weight. The point below which a worn coin ceases to be legal tender.

The remedy figures look arbitrary in grammes and are tidy in grains, which is the unit they were originally set in: 0.15, 0.2, 0.4 and 1 grain. A grain is 0.06479891 g, so one grain is 0.06480 g at five decimal places. The Act also allows a remedy on fineness as well as on weight.

Two things follow from this that are worth holding on to.

First, a struck sovereign is legally permitted to weigh anywhere from 7.97509 g to 8.00101 g and still be a correctly made coin. If your scale reads 7.98 g on a coin that has never circulated, nothing is wrong.

Second, the sovereign's status as legal tender is what makes it exempt from Capital Gains Tax in the UK, not its gold content. That distinction is explained in our guide to capital gains tax on gold in the UK. Tax treatment depends on your individual circumstances and can change.

Why 22 carat and not 24

Twenty-two carat gold, in British coinage, is called crown gold. It is eleven parts fine gold to one part alloy, and it has been the coinage standard since Henry VIII introduced it in 1526 for the gold crown.

The reason is wear. Pure gold is soft. A 24 carat coin passed hand to hand loses metal quickly, and for a circulating currency backed by its own metal content that is a direct loss to whoever holds it. Adding a twelfth part of harder metal makes the coin substantially more durable while keeping the colour recognisably gold.

The trade was made deliberately. The older sovereign of Henry VII, first struck in 1489, was 23 carat 3.5 grains, which is roughly 0.9948 fine and effectively near pure, and it weighed 240 grains (about 15.55 g). The move to crown gold gave up a little purity for a coin that could survive circulation.

What the alloy actually is

In sovereigns struck in London, the one twelfth part is copper. That is what gives a sovereign its warm, faintly reddish tone against the flat yellow of a 24 carat coin.

British and branch-mint sovereigns weigh the same

A British sovereign and a branch-mint sovereign are the same coin to the same specification. Coins struck in Sydney from 1855, and later Melbourne, Perth, Ottawa, Bombay and Pretoria, were made to the identical statutory weight and fineness as London-struck coins. The alloy in the naturally occurring Australian gold carried silver rather than copper, which produces a paler, yellower coin. The weight is the same, the fine gold content is the same, only the colour differs.

The Britannia takes the opposite approach and has been struck at 999.9 fineness since 2013. That comparison is set out below, and in more depth in our guide to gold sovereign versus Britannia.

Thickness, and why callipers disagree with the spec sheet

This is the specification that causes the most confusion, because published figures for the sovereign range from about 1.0 mm to 1.52 mm depending on the source. They are measuring different things.

A sovereign is not a flat disc. It has a raised rim, a recessed field and a raised design. The 1.52 mm figure is the maximum thickness, taken across the rim. Figures near 1.0 mm are readings taken across the field, the recessed area inside the rim. Put your callipers in different places and you will get different answers, and both will be honest.

You can work out the average thickness from the volume. Twenty-two carat sovereign alloy has a density of about 17.7 g per cubic centimetre.

1. Volume is 7.98805 divided by 17.7, which is 0.4513 cubic centimetres, or 451.3 cubic millimetres.
2. Face area is pi multiplied by 11.025 squared, which is 381.9 square millimetres.
3. Average thickness is 451.3 divided by 381.9, which is 1.18 mm.

So a sovereign is roughly 1.18 mm thick on average and 1.52 mm at its thickest point. Run the same calculation across the family and it produces the averages below. These are our own derived figures rather than The Royal Mint's, and they are averages rather than calliper readings.

One practical consequence: a quarter sovereign and a half sovereign are close to the same average thickness as each other, and both are noticeably thinner than a full sovereign. If you are handling them, thickness will not help you tell the two smaller coins apart. Diameter will, and by a wide margin: 13.50 mm against 19.30 mm.

Turning weight into gold content, and into money

The gold content of any sovereign is its fine gold weight in troy ounces multiplied by the gold price per troy ounce. The multipliers are fixed.

Two more conversions that come up often:

• It takes 136.57 sovereigns to hold one kilogram of fine gold.
• It takes 125.19 sovereigns to weigh one kilogram gross.

At a live gold price of £3,390.98 per troy ounce as at 21 August 2026, multiply by 0.235420 for the gold content of one full sovereign, or by 0.117710 for a half.

That figure is the metal content, not the price. Sovereigns trade at a premium to their gold content, and the premium varies with the year, the mint, the condition and, for graded coins, the grade. Three things follow that are easy to overlook. There is a spread between the price you buy at and the price you sell at, so the premium paid on purchase is not necessarily recovered on sale. Vault storage, where it is used, carries a charge. And gold prices fall as well as rise, so the value of a coin can fall below what you paid for it.

Our guide to gold sovereign price sets out how premiums are formed, and selling gold sovereigns covers the same arithmetic in reverse.

Sovereign against a one-ounce Britannia

The sovereign and the Britannia are the two main UK legal tender bullion coins, and they take different approaches to the same job. The Queen's Beasts, Lunar and commemorative gold issues are UK legal tender gold too, but the sovereign and the Britannia are the two most buyers are choosing between.

Gross weight is left out of that table deliberately. The Royal Mint publishes a weight of 31.21 g for the one-ounce gold Britannia, and the coin is guaranteed to contain one troy ounce of fine gold, which is 31.1035 g. Those two figures do not reconcile as a simple fineness multiple: 31.21 g at 999.9 would hold 31.2069 g of gold, and one troy ounce of fine gold at 999.9 would need a gross coin of 31.1066 g. Rather than print a number that fails its own arithmetic, we quote the fine gold content, which is the figure that matters for valuation, and refer you to The Royal Mint's published specification for the gross weight.

One further point on the Britannia. The 999.9 standard applies from 2013 onwards. Britannias struck from 1987 to 2012 are 916.7 fine, the same 22 carat standard as the sovereign, so their gross weight differs from a modern coin's. Check the year before applying any specification.

It takes 4.2477 sovereigns to hold the gold in a single one-ounce Britannia. Both are UK legal tender and both are exempt from Capital Gains Tax on that basis. The sovereign divides a holding into smaller units, which matters if you may want to sell part of a position rather than all of it. The Britannia carries more gold per coin, and being 24 carat it marks more easily, which is one reason those coins are usually handled less.

What weight tells you about a coin, and what it does not

Weight is the first check most people reach for. It is worth being clear about what it can and cannot settle.

A circulated sovereign will usually be light

A coin that spent forty years in circulation has lost gold. That is what the least current weight of 7.93787 g in the Coinage Act 1971 exists to acknowledge. A genuine Victorian sovereign reading 7.94 g or 7.95 g is a normal, worn, genuine coin. Modern uncirculated sovereigns should sit within the remedy band of 7.97509 g to 8.00101 g.

If your scale reads below 7.93787 g, the coin has worn past the least current weight and is no longer legal tender at its face value. In practice that matters less than it sounds. The coin is still gold and still saleable, priced on its assayed gold content rather than as a collectable, though most of the premium a better coin would carry has gone with the metal.

Weight alone cannot confirm authenticity

A counterfeit made to the correct weight is not difficult. Density is a weaker test than it looks as well. Tungsten sits at about 19.25 g per cubic centimetre against gold's 19.32, close enough that a tungsten core in a gold shell can defeat a specific gravity reading. That is a serious problem in large bars, where there is room to hide a core. In a coin 22.05 mm across and a little over a millimetre thick the tolerances are far tighter and the trick is much harder to execute, but a specific gravity reading on its own still does not settle the question.

Weight combined with diameter and thickness is a meaningfully stronger check than any one of the three, because a fake has to be right on all of them at once and the specification leaves very little room. It is still an inference rather than a verification.

Checks you can run yourself

Three checks are cheap, and they are worth doing together rather than one at a time.

• A gauge slot. A slot cut to the diameter and thickness of a sovereign will reject a coin that is right on weight but wrong on dimensions. A fake that makes up weight with a bulkier or denser core usually fails here.
• The ping test. Balanced on a fingertip and tapped lightly, a gold coin rings at a characteristic pitch and holds the note. A base metal core tends to give a shorter, duller sound. Phone applications will read the frequency for you. It is an indicator, not proof.
• Conductivity. A precious metal verifier of the Sigma Metalytics type reads electrical resistivity through the coin rather than at its surface, so a plated fake shows up. The instruments cost a few hundred pounds, which is worth it if you buy regularly and not if you buy once.

None of these is conclusive alone. Together with weight and dimensions they make a competent fake considerably harder to pass.

What settles it

Independent grading. The coins we supply are independently graded and encapsulated by NGC or PCGS, and each carries a serial number you can enter into the grading service's own certification verification lookup before you buy, which returns the grade and specification that service recorded for that exact coin. The population report is a different tool: it shows how many coins of a type have been graded at each level, not whether the coin in front of you is what it claims to be.

There is a trade-off here, and it is fairer to name it than to argue it away. A graded coin is sealed, so you cannot put it on your own scale without breaking the holder and losing the grade. You are exchanging one form of verification for another: your own measurement, which as this page has set out cannot settle authenticity by itself, for a third party's assessment recorded against a number you can check independently. If handling and weighing the coin yourself matters more to you than that, an ungraded coin is the better fit. Our page on independently graded coins explains how the grades are assigned and what they mean for value.

Buying a sovereign to specification

If you are working out what a sovereign is worth, the sequence is fine gold weight, then gold price, then premium. The first is fixed and published above. The second moves daily and nobody can time it. The third varies with year, mint, condition and grade, and it takes some work to read.

Bullion Club supplies NGC and PCGS graded Royal Mint gold coins to UK investors. Every coin is independently graded and verifiable by serial number. Delivery is fully insured and next-day, or coins can be held in segregated vault storage with audit rights. We buy back coins we have supplied at prevailing market rates, with settlement typically within 48 hours of the coins being verified. Our Feefo rating is 5 out of 5 from 225 verified reviews, as at 21 August 2026.

If you want to talk through how the denominations and grades compare, you can book a call with one of our team.

Important information

• Investment in physical gold is not regulated in the UK. You will not have the protection of the Financial Conduct Authority, cover under the Financial Services Compensation Scheme, or access to the Financial Ombudsman Service.
• The value of gold and of gold coins falls as well as rises. You may get back less than you paid. Buying and selling prices differ, and storage carries a charge where it is used.
• UK legal tender gold coins including the sovereign and the Britannia are exempt from Capital Gains Tax. Investment gold meeting the HMRC definition is exempt from VAT; for coins, HMRC's conditions include a gold purity of not less than 900 thousandths, minting after 1800, legal tender status in the country of origin, and a normal selling price no higher than 180 per cent of the open market value of the gold the coin contains. Sovereigns and Britannias meet those conditions. Tax treatment depends on your individual circumstances and can change.
• Nothing on this page is investment advice or tax advice.

Frequently asked questions

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