US Proof to ABV Fraction for Alcohol Strength

Snapshot

1 US Proof equals 0.005 ABV Fraction. Conversion Encyclopedia uses the same fixed conversion basis across the calculator, common values, and reverse page for this page.

Reference basis: This result uses fixed ABV and proof definitions for the selected alcohol-strength pair.
Example: For 0.25 US Proof, the result equals 0.00125 ABV Fraction.
Use the reverse page if you need the opposite direction with the same basis.

Use the interactive calculator below for custom values and the common-value table for quick checks.

Converter Calculator

0.005 ABV Fraction (fraction)

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Explanation

Formula: ABV Fraction = US Proof × 0.005. 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.

ABV Fraction (fraction): a 0-to-1 alcohol-strength representation where 1 equals 100% 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 = 0.005 ABV Fraction.
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))	ABV Fraction (fraction)
0.25	0.00125
0.5	0.0025
1	0.005
5	0.025
12	0.06
20	0.1
40	0.2
57.15	0.28575
80	0.4
100	0.5

Frequently Asked Questions

How many fraction are in 1 proof (US)?

1 proof (US) equals 0.005 fraction on this page.

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 ABV Fraction?

Use the switch button or open the ABV Fraction 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.