# Gallons to Grams Converter (by Liquid)

URL: https://speedycalculator.com/calculators/conversion/gallons-to-grams/
Last updated: 2026-10-25

> Convert US gallons to grams for water (20 °c) and 17 other substances, or enter your own density. Because US gallons measure volume and grams measure weight, the result depends on the substance: mass = volume × density.

## Inputs

- Substance
- Custom density (g/cm³, kg/m³, kg/L, lb/ft³, lb/US gal)
- US gallons (US gal, L, mL, cL, dL, m³, cm³ (cc), µL, UK gal, US dry gal, US qt, UK qt, US pt, UK pt, US cup, metric cup, US fl oz, UK fl oz, tbsp, tsp, drop, ft³, in³, yd³, CCF, acre-ft, bbl)

## Results

- Density used
- Grams
- Kilograms
- Pounds

## Formula

```
mass = volume × density
```

## Explanation

A U.S. gallon of water weighs about 3,779 g. Brewers, soap makers and chemists working in gallons convert to grams for recipes and formulations.

### How to use the Gallons to Grams Converter

- **Substance**
- **Custom density**
- **US gallons**
- Every result field is editable: type into **Grams** or any other result and **US gallons** plus every other field update to match.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

The calculator converts your volume to SI units, looks up the density of the selected substance in kg/m³ and multiplies. The result is then shown in grams and other common units. Every result field is editable, so you can work backwards too.

### How to convert US gallons to grams

- Find the density of the substance (the menu fills it in for you).
- Convert the volume to SI units if needed.
- Multiply volume by density to get mass.
- Convert the answer to grams.

### 1 US gallon of common substances in grams

SubstanceGrams per 1 US galWater (4 °C)3,785.4118Water (20 °C)3,778.598Water (100 °C)3,627.9387Seawater3,880.0471Milk3,898.9741Gasoline (petrol)2,820.1318Diesel3,179.7459Jet fuel (Jet A)3,043.4711Kerosene3,066.1835Crude oil (typical)3,293.3083Ethanol2,986.6899Propane (liquid)1,866.208Olive oil3,456.081Vegetable oil3,486.3643Honey5,375.2847Beer3,823.2659Orange juice3,955.7553Latex paint (typical)4,921.0353

### Densities used

Substancekg/m³g/mLlb/US galWater (4 °C)1,00018.3454045Water (20 °C)998.20.99828.3303827Water (100 °C)958.40.95847.9982356Seawater1,0251.0258.5540396Milk1,0301.038.5957666Gasoline (petrol)7450.7456.2173263Diesel8400.847.0101397Jet fuel (Jet A)8040.8046.7097052Kerosene8100.816.7597776Crude oil (typical)8700.877.2605019Ethanol7890.7896.5845241Propane (liquid)4930.4934.1142844Olive oil9130.9137.6193543Vegetable oil9210.9217.6861175Honey1,4201.4211.850474Beer1,0101.018.4288585Orange juice1,0451.0458.7209477Latex paint (typical)1,3001.310.849026

### Inputs explained

FieldWhat to enterSubstanceChoose one: Water (4 °C), Water (20 °C), Water (100 °C), Seawater …Custom densityUnits: g/cm³, kg/m³, kg/L, lb/ft³, lb/US galUS gallonsUnits: US gal, L, mL, cL, dL, m³ …

### What each result means

- **Grams** = [US gallons] × [Density used]
- **Kilograms** = [US gallons] × [Density used]
- **Pounds** = [US gallons] × [Density used]

## Worked example

Inputs — Substance: Water (20 °C); Custom density: 1 g/cm³; US gallons: 1 US gal.

Results — Density used = 0.9982 g/cm³; **Grams = 3,778.598043 g**; Kilograms = 3.778598 kg; Pounds = 8.330383 lb.

## FAQ

**How many grams in a gallon of water?**
About 3,779 g at 20 °C.

**How many grams is a gallon of milk?**
About 3,899 g.

**Why does the answer change with the ingredient?**
US gallons and grams measure different things (volume and weight), so the conversion depends on how dense the material is.

**What if my ingredient is not listed?**
Choose “Custom density” and type its density; the label or a quick weigh-and-measure test will give it.

**What formula does the Gallons to Grams Converter use?**
mass = volume × density.


## Sources

- [The Engineering ToolBox – Densities of liquids and solids](https://www.engineeringtoolbox.com/density-solids-d_1265.html)