Weight-to-proof-gallons calculator

The Weight to Proof Gallons calculator is for distillers who gauge by scale — a weight is often more precise than a dip, especially for a package. It has two panels: Weight → gallons turns a net weight into wine gallons and proof gallons using the per-pound factors from the Gauging Manual's Table 4, and Wine ↔ proof gallons converts between wine gallons and proof gallons at a given proof. Both follow the 27 CFR §30.62–§30.66 conversions and round to a tenth of a gallon, as those sections prescribe.

It's free, needs no account, and computes in your browser.

Open the calculator

• On the public site: in the top navigation choose Tools, then on the Weight to Proof Gallons card choose Open calculator.
• Inside the app: in the navigation choose Tools, then on the Weight to Proof Gallons card choose Open calculator.

Convert a net weight to gallons

This uses the Weight → gallons panel. You supply the per-pound factors for your spirit's proof, read from your own copy of the Gauging Manual's Table 4 — the calculator doesn't look them up for you, so it works at any proof.

1. In Net weight (lb), enter the net weight of spirits, in pounds.
2. In Wine gal / lb (Table 4), enter the wine-gallons-per-pound factor for your spirit's proof.
3. Wine gallons appears immediately.
4. To also get proof gallons, enter the proof-gallons-per-pound factor for that proof in Proof gal / lb (Table 4, optional). Proof gallons then appears alongside.

Worked example

Gauging 81,000 lb of spirit whose Table 4 factors are 0.14718 wine gallons and 0.27964 proof gallons per pound:

1. Net weight (lb): 81000
2. Wine gal / lb (Table 4): 0.14718
3. Proof gal / lb (Table 4, optional): 0.27964

The calculator shows Wine gallons 11,921.6 and Proof gallons 22,650.8 — each rounded to a tenth of a gallon per §30.63/§30.64.

Convert between wine and proof gallons

This uses the Wine ↔ proof gallons panel — the proof-gallon definition (proof gallons = wine gallons × proof ÷ 100) run either direction.

1. In the Convert list, choose the direction: Wine gallons → proof gallons or Proof gallons → wine gallons.
2. Enter the starting figure in the input (its label follows your choice — Wine gallons or Proof gallons).
3. In Proof, enter the true proof — over 0 and up to 200.
4. The converted figure appears, labelled with the output unit.

Worked example

Converting 42.8 wine gallons at 96.8° proof to proof gallons:

1. Convert: Wine gallons → proof gallons
2. Wine gallons: 42.8
3. Proof: 96.8

The calculator shows Proof gallons 41.4.

When to reach for it

Reach for the Weight → gallons panel when you gauge a package or tank by weighing it and want wine and proof gallons from the scale reading — bring the Table 4 factors for your proof. Reach for Wine ↔ proof gallons for the everyday back-and-forth between the two units at a known proof; if you're starting from a measured volume rather than gallons, the Proof gallons calculator does the volume-to-gallons step for you.

The calculator notes on-screen that it's a quick estimate for reference — a tool, not an official TTB filing or gauge record — that the per-pound factors come from the Gauging Manual's Table 4 for your spirit's proof, and that results are rounded to a tenth of a gallon per §30.63/§30.64.