Gallons to kg Converter
1 US gallon of water weighs about 3.785 kg, 1 gallon of milk is about 3.899 kg, and 1 gallon of gasoline is about 2.839 kg. This gallons to kg converter switches between volume and weight using each substance's density. Enter a value, choose the direction, pick a preset for water, milk, gasoline, or honey, or type a custom density in kilograms per liter from a label or spec sheet. Gallons to kilograms is a common conversion for people shipping liquids, buying in bulk, or comparing product weights from labels that use different unit systems. A gallon of water is the reference point at about 3.785 kg, but every other liquid lands above or below that number depending on how tightly its molecules pack together. Milk is slightly denser than water, so a gallon weighs a little more. Gasoline is lighter, so a gallon weighs less. Honey is much denser, so a gallon weighs nearly one and a half times as much as water. The conversion depends on both the gallon definition and the density value. This converter uses the US liquid gallon of exactly 3.785411784 liters. If you are working with British imperial gallons of about 4.546 liters, convert to liters first or the result will be about 20 percent low.
Quick answer
Gallons measure volume and kilograms measure weight, so the conversion depends entirely on what liquid fills the container.
Result
3.7854 kg
Density used
1 kg/L
What this tells you
- •Gallons measure volume and kilograms measure weight, so the conversion depends entirely on what liquid fills the container.
- •Use gallons to kg when you know the volume and need the weight for shipping, batching, or inventory.
- •Use kg to gallons when you know the weight and need to estimate how much space the liquid will take.
- •Water is the easy reference at about 3.785 kg per gallon, but every other liquid lands above or below that number.
- •Higher density means more kilograms per gallon. Honey at 1.42 kg/L comes to about 5.375 kg per gallon.
- •Custom density is useful for fuel blends, cleaning liquids, sauces, or any product not covered by a preset.
How to Use
- 1Enter the amount you already have. Use a gallon value if you know the volume, or a kilogram value if you know the weight.
- 2Choose the direction. Select gal to kg when turning volume into weight, or kg to gal when turning weight into volume.
- 3Pick a substance preset if your liquid matches water, milk, gasoline, or honey.
- 4Select custom density and enter a value in kg/L if you have a more exact number from packaging or a technical data sheet.
- 5Read the result. The density used is shown so you can verify it matches your expected value.
How It Works
Formula
kg = gallons x 3.785411784 x density (kg/L)To convert gallons to kilograms, multiply the volume by 3.785411784 liters per US gallon to get liters, then multiply by the density in kilograms per liter. For water at 1 kg/L, 1 gallon times 3.785411784 times 1 equals about 3.785 kg. For milk at 1.03 kg/L, 3 gallons times 3.785411784 times 1.03 equals about 11.696 kg. To convert kilograms to gallons, divide the weight by the density in kg/L times 3.785411784.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
1 gallon of water to kg
Multiply 1 by 3.785411784 liters per gallon, then by 1 kg/L to get about 3.785 kg.
3 gallons of milk to kg
Multiply 3 by 3.785411784 to get 11.356 liters, then by 1.03 kg/L for milk to get about 11.696 kg.
10 gallons of gasoline to kg
Gasoline is lighter at 0.75 kg/L. Multiply 10 by 3.785411784 by 0.75 to get about 28.391 kg.
Gallons to Kilograms by Substance
| Substance | Density (kg/L) | 1 gal in kg | 1 kg in gal |
|---|---|---|---|
| Water | 1.00 | 3.785 kg | 0.264 gal |
| Milk | 1.03 | 3.899 kg | 0.257 gal |
| Gasoline | 0.75 | 2.839 kg | 0.352 gal |
| Honey | 1.42 | 5.375 kg | 0.186 gal |
Common mistakes
- Assuming 1 gallon always equals a fixed number of kilograms. The answer depends on density, so water, milk, gasoline, and honey all give different results.
- Using the wrong conversion direction. Gallons to kg is multiplication, kg to gallons is division.
- Mixing gallon standards. This converter uses the US liquid gallon of 3.785411784 liters. The imperial gallon used in the UK is about 4.546 liters and would give a different result.
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