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
| Substance | Grams per 1 US gal |
|---|---|
| Water (4 °C) | 3,785.4118 |
| Water (20 °C) | 3,778.598 |
| Water (100 °C) | 3,627.9387 |
| Seawater | 3,880.0471 |
| Milk | 3,898.9741 |
| Gasoline (petrol) | 2,820.1318 |
| Diesel | 3,179.7459 |
| Jet fuel (Jet A) | 3,043.4711 |
| Kerosene | 3,066.1835 |
| Crude oil (typical) | 3,293.3083 |
| Ethanol | 2,986.6899 |
| Propane (liquid) | 1,866.208 |
| Olive oil | 3,456.081 |
| Vegetable oil | 3,486.3643 |
| Honey | 5,375.2847 |
| Beer | 3,823.2659 |
| Orange juice | 3,955.7553 |
| Latex paint (typical) | 4,921.0353 |
Densities used
| Substance | kg/m³ | g/mL | lb/US gal |
|---|---|---|---|
| Water (4 °C) | 1,000 | 1 | 8.3454045 |
| Water (20 °C) | 998.2 | 0.9982 | 8.3303827 |
| Water (100 °C) | 958.4 | 0.9584 | 7.9982356 |
| Seawater | 1,025 | 1.025 | 8.5540396 |
| Milk | 1,030 | 1.03 | 8.5957666 |
| Gasoline (petrol) | 745 | 0.745 | 6.2173263 |
| Diesel | 840 | 0.84 | 7.0101397 |
| Jet fuel (Jet A) | 804 | 0.804 | 6.7097052 |
| Kerosene | 810 | 0.81 | 6.7597776 |
| Crude oil (typical) | 870 | 0.87 | 7.2605019 |
| Ethanol | 789 | 0.789 | 6.5845241 |
| Propane (liquid) | 493 | 0.493 | 4.1142844 |
| Olive oil | 913 | 0.913 | 7.6193543 |
| Vegetable oil | 921 | 0.921 | 7.6861175 |
| Honey | 1,420 | 1.42 | 11.850474 |
| Beer | 1,010 | 1.01 | 8.4288585 |
| Orange juice | 1,045 | 1.045 | 8.7209477 |
| Latex paint (typical) | 1,300 | 1.3 | 10.849026 |
Inputs explained
| Field | What to enter |
|---|---|
| Substance | Choose one: Water (4 °C), Water (20 °C), Water (100 °C), Seawater … |
| Custom density | Units: g/cm³, kg/m³, kg/L, lb/ft³, lb/US gal |
| US gallons | Units: 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]
Formula
mass = volume × densityWorked 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.
Frequently asked questions
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.