How many units in a shot of vodka?
The UK unit count for any measure of spirits, from size and ABV, using the NHS formula.
A single 25 ml shot of 40% vodka is exactly 1 UK unit — the tidiest sum in the system. A 50 ml double is 2 units, and a 25 ml shot of weaker 37.5% supermarket vodka comes to 0.9.
The units in a shot of vodka depend on two things
your bar doesn't always advertise: the measure it pours, and the
strength of the bottle. A UK unit is 10 mL (8 g) of pure alcohol, so
the sum is volume × ABV ÷ 1000. Because a 25 ml
measure of a 40% spirit lands on exactly 1.0, spirits are the easiest
drink to count in your head — provided you know which measure you
were served.
| Measure | 37.5% (supermarket) | 40% (standard) | 50% (overproof) |
|---|---|---|---|
| Single, 25 mL | 0.9 | 1.0 | 1.3 |
| Single, 35 mL | 1.3 | 1.4 | 1.8 |
| Double, 50 mL | 1.9 | 2.0 | 2.5 |
| Double, 70 mL | 2.6 | 2.8 | 3.5 |
| Bottle | Units at 37.5% | Units at 40% | 25 mL shots |
|---|---|---|---|
| Quarter, 175 mL | 6.6 | 7.0 | 7 |
| Half, 350 mL | 13.1 | 14.0 | 14 |
| Standard, 700 mL | 26.3 | 28.0 | 28 |
| Litre, 1,000 mL | 37.5 | 40.0 | 40 |
Singles, doubles, and the 25 vs 35 ml problem
UK licensing law lets a venue sell spirits in either 25 ml or 35 ml measures, but it has to choose one and display which. England and Wales mostly pour 25 ml; Scotland and Northern Ireland commonly use 35 ml. That means the same "single vodka and coke" is 1 unit in one pub and 1.4 in another, a 40% difference for an identical order.
Doubles compound it. Plenty of bars pour doubles by default unless you specify a single, and a 50 ml double of 40% vodka is 2 units. Four of those is 8 units in an evening, more than half the weekly low-risk guideline of 14.
The mixer doesn't count
A common misreading: tonic, cola and juice contain no alcohol, so they add nothing to the unit count. A double vodka and soda in a tall glass is 2 units, exactly the same as a double poured neat. The glass size tells you nothing; only the measure does.
Counting a whole bottle instead? A 700 ml bottle of 37.5% vodka is 26.3 units — close to double the weekly guideline — and holds 28 single 25 ml shots.
How this calculator works
The math: units = volume (mL) × ABV ÷ 1000. A "unit" here is the UK unit, defined by the NHS as 10 mL or 8 g of pure alcohol. The weekly-share figure compares the total against the UK Chief Medical Officers' 14-unit low-risk guideline, which is a guideline, not a threshold below which drinking carries no risk.
Full formulas and citations live on the methodology page.
Units in a shot of vodka: questions people ask
How many units are in a double vodka?
A 50 mL double of 40% vodka is 2 UK units. At 37.5% ABV it is 1.9 units. Many UK bars pour doubles as standard unless you ask for a single, so a night of four drinks can quietly be eight units.
Is a UK shot 25 mL or 35 mL?
Both are legal. UK licensing law requires spirits to be sold in 25 mL or 35 mL measures, and a venue must pick one and display which it uses. England and Wales lean towards 25 mL; Scotland and Northern Ireland commonly use 35 mL. A 35 mL shot of 40% vodka is 1.4 units.
How many units are in a bottle of vodka?
A 700 mL bottle of 37.5% vodka contains 26.3 UK units. At 40% ABV the same bottle is 28 units. Either way a single bottle is roughly twice the 14-unit weekly guideline, and holds 28 single 25 mL shots.
Does the mixer change the units?
No. Tonic, cola and juice contain no alcohol, so a vodka and coke has exactly the same units as the vodka poured into it. A double vodka and coke is 2 units whether it arrives in a small glass or a tall one.
Is a shot of vodka the same as a US standard drink?
Close, but not identical. The US standard pour is 1.5 fl oz (44 mL) at 40%, which is one US standard drink of 14 g. A UK 25 mL single at 40% is 1 UK unit, or 8 g — about 57% of a US standard drink. Use the standard drinks calculator for the US figure.