US Proof to UK Proof for Alcohol Strength

1 US Proof equals 0.874891 UK Proof using fixed ABV and proof definitions used in beverage labeling and spirits references.

Direct Answer

1 US Proof equals 0.874891 UK Proof

This result uses fixed ABV and proof definitions for the selected alcohol-strength pair.

For 0.25 US Proof, the result equals 0.218723 UK Proof.

Converter Calculator

0.874891 UK Proof (proof (UK))

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Explanation

Formula: UK Proof = US Proof × 0.874891. Why: proof scales are normalized through ABV percent using fixed legal definitions, including US proof = 2 times ABV and 100 UK proof = 57.15% ABV.

US Proof (proof (US)): a spirits-strength scale defined as exactly 2 times ABV percent.

UK Proof (proof (UK)): a historical proof scale where 100 proof equals 57.15% ABV.

This route is useful when translating between ABV and proof systems for beverage labeling, spirits references, and dilution planning.

This conversion is purely multiplicative because both strength scales reduce through ABV percent using fixed proof and fractional definitions with no offset.

Method & Strength Basis

  • Method basis: fixed alcohol-strength definitions normalized through ABV percent, including the exact US and UK proof relationships used on this page.
  • Applied factor: 1 US Proof = 0.874891 UK Proof.
  • Consistency rule: calculator output and common-value rows use the same ABV-based strength constants in both directions.

Common Conversion Values

US Proof (proof (US))UK Proof (proof (UK))
0.25 0.218723
0.5 0.437445
1 0.874891
5 4.374453
12 10.498688
20 17.497813
40 34.995626
57.15 50
80 69.991251
100 87.489064

Frequently Asked Questions

Why does this route go through ABV percent?

ABV percent is the common reference layer for this family, so proof, fraction, and per-mille strength values stay consistent and reversible.

How do I reverse US Proof to UK Proof?

Use the switch button or open the UK Proof to US Proof page to apply the same alcohol-strength relationship in reverse.

Can I use decimal inputs?

Yes. Decimal strength values are supported for beverage labeling, spirits references, lab work, and batching calculations.