# Gallons to kg Converter (by Liquid)

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

> Convert US gallons to kilograms for diesel and 17 other substances, or enter your own density. Because US gallons measure volume and kilograms 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
- Kilograms
- Pounds
- Grams

## Formula

```
mass = volume × density
```

## Explanation

Multiply gallons by 3.785 to get litres, then by the density in kg/L. A U.S. gallon of diesel weighs about 3.18 kg.

### How to use the Gallons to kg Converter

- **Substance**
- **Custom density**
- **US gallons**
- Every result field is editable: type into **Kilograms** 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 kilograms and other common units. Every result field is editable, so you can work backwards too.

### How to convert US gallons to kilograms

- 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 kilograms.

### 1 US gallon of common substances in kilograms

SubstanceKilograms per 1 US galWater (4 °C)3.7854118Water (20 °C)3.778598Water (100 °C)3.6279387Seawater3.8800471Milk3.8989741Gasoline (petrol)2.8201318Diesel3.1797459Jet fuel (Jet A)3.0434711Kerosene3.0661835Crude oil (typical)3.2933083Ethanol2.9866899Propane (liquid)1.866208Olive oil3.456081Vegetable oil3.4863643Honey5.3752847Beer3.8232659Orange juice3.9557553Latex paint (typical)4.9210353

### 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

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

## Worked example

Inputs — Substance: Diesel; Custom density: 1 g/cm³; US gallons: 1 US gal.

Results — Density used = 0.84 g/cm³; **Kilograms = 3.179746 kg**; Pounds = 7.01014 lb; Grams = 3,179.745899 g.

## FAQ

**How many kg is a gallon of water?**
About 3.78 kg.

**How many kg is a gallon of diesel?**
About 3.18 kg.

**Why does the answer change with the ingredient?**
US gallons and kilograms 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 kg Converter use?**
mass = volume × density.


## Sources

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