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Proof to ABV Alcohol Converter

US Proof = ABV% × 2 | UK Proof = ABV% × 1.7513

Example: A standard 80 Proof vodka is equivalent to exactly 40.0% Alcohol By Volume (ABV).

Convert beverage alcohol content parameters. Convert between US Proof, UK Proof (Sikes scale), and ABV percentage.

Alcohol By Volume

%

Calculated Proof

US Proof Rating 80.0 Proof
UK Proof Rating 70.1 Proof

Standard Beverage Strengths

Beverage Description ABV % US Proof Equivalent UK Proof Equivalent
Standard Light Beer 4.2% 8.4 Proof 7.4 Proof
Regular Beer / Lager 5.0% 10.0 Proof 8.8 Proof
Hard Cider / Seltzer 8.0% 16.0 Proof 14.0 Proof
Standard Wine 12.0% 24.0 Proof 21.0 Proof
Fortified Wine (Port) 20.0% 40.0 Proof 35.0 Proof
Liqueurs (Triple Sec) 30.0% 60.0 Proof 52.5 Proof
Standard Spirits (Vodka, Gin) 40.0% 80.0 Proof 70.1 Proof
Cask Strength Whiskey 55.0% 110.0 Proof 96.3 Proof
Overproof Rum / Grain Alcohol 75.5% 151.0 Proof 132.2 Proof

US vs UK Proof: History & Difference

The origin of "proof" comes from 18th century Britain where customs officials needed to verify spirit strength. They soaked gunpowder in the spirit: if it ignited, the spirit was "proven" strong enough for taxation purposes. The threshold was approximately 57.1% ABV, which became 100 British Proof.

The US adopted a simpler system in 1848: 1 Proof = 0.5% ABV. So 100 US Proof = 50% ABV. This means the two systems are on different scales: 80 US Proof = 40% ABV, while 80 UK Proof = 45.7% ABV.

Responsible Drinking & Standard Drinks

A "standard drink" in the US contains 14 grams of pure alcohol:

Beer (5% ABV)12 oz / 355 mL
Wine (12% ABV)5 oz / 148 mL
Spirits (40% ABV)1.5 oz / 44 mL
UK unit = 10 mL pure alcohol≈ 8g

Frequently Asked Questions — Alcohol Proof

What does "proof" mean for alcohol?
In the US, "proof" is simply twice the ABV percentage. A 80 Proof spirit is 40% ABV, a 100 Proof spirit is 50% ABV. The term dates from 18th century Britain, where gunpowder soaked in spirit would ignite only if the spirit was at or above 57% ABV — that was proof the spirits were strong enough.
How do I convert US proof to ABV?
US Proof to ABV: divide by 2. ABV = US Proof / 2. For example: 80 Proof vodka = 80/2 = 40% ABV. 70 Proof whiskey = 70/2 = 35% ABV. 100 Proof bourbon = 100/2 = 50% ABV.
What is UK Proof (Sikes scale)?
UK Proof uses the Sikes scale where "100 proof" = 57.15% ABV (not 50% like US). The conversion is: UK Proof = ABV × 1.7513. So 40% ABV spirit = 70.1 UK Proof. The UK abolished its proof system in 1980 and now uses ABV exclusively.
What is the ABV of common alcoholic beverages?
Light beer: 3.5–4.2% ABV (7–8.4 US Proof). Regular beer: 4.2–5.5% ABV. Wine: 11–14% ABV (22–28 US Proof). Standard spirits (vodka, gin, rum, whiskey): 40% ABV (80 US Proof). Cask strength whiskey: 55–65% ABV (110–130 US Proof).
What does "overproof" mean?
Overproof spirits have an ABV above 50% (above 100 US Proof). Overproof rum (like Bacardi 151, 75.5% ABV, 151 Proof) is used mainly for cooking flames and cocktail floats. High-proof Everclear grain alcohol reaches 95% ABV (190 Proof) — flammable and dangerous to consume neat.

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