# How do I convert gallons to lbs?

Converts gallons to pounds and back for water, milk, flour, sugar, and other ingredients, from what each one weighs per liter.

- Page: https://www.acalculator.org/convert/gallons-to-lbs
- JSON spec: https://www.acalculator.org/convert/gallons-to-lbs.json
- Version: 7acc5f8a44a4

## Default answer

Example with the default inputs (Gallons (gal) 1, Ingredient Water at 4 °C, 0.999975 kg per L): 1 gal = 8.345196 lb (Water at 4 °C, 0.999975 kg per L).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Gallons (gal) | The amount in gallons to convert. |
| result | Pounds (lb) | The same amount in pounds. |
| ingredient | Ingredient | What you are measuring. A cup of flour weighs less than a cup of water. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Gallons (gal) | The amount in gallons to convert. |
| result | Pounds (lb) | The amount in pounds. |

## Method

lbs = gallons × 3.785411784 × 0.999975 ÷ 0.45359237, where kilograms per liter depends on the ingredient (water at 4 °C: 0.999975 kg)

## Assumptions

- Grams per cup are USDA FoodData Central (SR Legacy) portion weights for one level US cup (8 US fluid ounces): all-purpose flour 125 g (FDC 168894), granulated sugar 200 g (FDC 169655), brown sugar, packed 220 g (FDC 168833), powdered sugar, unsifted 120 g (FDC 169656), whole milk 244 g (FDC 171265), butter 227 g (FDC 173410), olive oil 216 g (FDC 171413), honey 339 g (FDC 169640), white rice, uncooked 185 g (FDC 169756).
- Water is pure water: 0.999975 kg per liter at 4 °C and 0.998207 kg per liter at 20 °C, from the Tanaka et al. (2001) density formula.
- Other ingredients use their USDA cup weight: kilograms per liter = grams per cup ÷ 236.5882365.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up; an answer of 1 billion or more shows at most 15 significant digits.

## Worked examples

1. value = 1, ingredient = water gives result = 8.345196. Source: Density of pure water from Tanaka et al. (2001), Metrologia 38, 301: 999.9749 kg/m³ at 4 °C, 998.2067 kg/m³ at 20 °C, as 0.999975 kg per liter.
2. value = 1, ingredient = milk gives result = 8.606847. Source: USDA FoodData Central SR Legacy 171265: 1 cup = 244 g.

## FAQ

### How many pounds are in a gallon?

It depends on the ingredient, because a volume does not fix the weight. 1 gal is about, in pounds: all-purpose flour 4.409; granulated sugar 7.055; brown sugar, packed 7.76; powdered sugar, unsifted 4.233; water at 4 °C 8.345; water at 20 °C 8.33; whole milk 8.607; butter 8.007; olive oil 7.619; honey 11.96; white rice, uncooked 6.526.

### How do I convert gallons to lbs?

lbs = gallons × 3.785411784 × 0.999975 ÷ 0.45359237, where kilograms per liter depends on the ingredient (water at 4 °C: 0.999975 kg). For example, 1 gal of water at 4 °C is 8.345196 lbs.

### Does a liter of water weigh 1 kg?

Almost. Pure water weighs 0.999975 kg per liter at 4 °C, where it is densest, and 0.998207 kg per liter at 20 °C (Tanaka et al. 2001). Other liquids differ more: a liter of whole milk weighs about 1.03 kg and a liter of olive oil about 0.91 kg (USDA).

### How much does a gallon of water weigh?

8.345196 lb at 4 °C, where water is densest, or 8.330441 lb at 20 °C: a US gallon is 3.785411784 L, and water weighs 0.999975 kg per liter at 4 °C and 0.998207 kg at 20 °C (Tanaka et al. 2001).

### How much does a gallon of milk weigh?

8.606847 lb: USDA lists a cup of whole milk at 244 g, and a gallon is 16 cups, 3,904 g.

## Sources

- USDA FoodData Central, SR Legacy portion weights for 1 cup: FDC 168894 all-purpose flour 125 g; FDC 169655 granulated sugar 200 g; FDC 168833 brown sugar, packed 220 g; FDC 169656 powdered sugar, unsifted 120 g; FDC 171265 whole milk 244 g; FDC 173410 butter 227 g; FDC 171413 olive oil 216 g; FDC 169640 honey 339 g; FDC 169756 white rice, uncooked 185 g, retrieved 2026-10-18. https://fdc.nal.usda.gov/
- Tanaka, M. et al. (2001), Recommended table for the density of water between 0 °C and 40 °C based on recent experimental reports, Metrologia 38, 301–309: pure water 999.9749 kg/m³ at 4 °C and 998.2067 kg/m³ at 20 °C, retrieved 2026-10-05. https://doi.org/10.1088/0026-1394/38/4/3
- NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8: Factors for Units Listed Alphabetically (bold factors are exact), retrieved 2026-10-18. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8