Kg to Gallons Converter
Convert kilograms to US gallons. Kilograms are weight and gallons are volume, so choose the substance — water, whole milk, vegetable oil, flour, sugar, honey, or butter — enter kg, and get US gallons and liters.
Example: with Weight in kilograms 20 · Substance Water (1.00 kg/L) → US gallons: 5.28 US gallons.
- In liters20 L
- How it converts20 kg ÷ 1 kg/L = 20 L; ÷ 3.7854 = 5.28 gal
Computed by the calculator below using its default values. Change any input to see your own numbers.
gallons = kg ÷ density (kg/L) ÷ 3.785411784. For water that collapses to kg ÷ 3.785 — one gallon of water weighs about 3.79 kg.
Kilograms measure mass, gallons measure space
There is no universal kg-to-gallon factor — the conversion runs through density. Divide kilograms by the substance's density in kg per liter to get liters, then by 3.785411784 to get US gallons. Water makes it easy: at about 1 kg/L, 20 kg of water is 20 liters, or 5.28 gallons. That is also why a gallon jug of water feels like roughly 3.8 kg on a scale.
Lighter liquids take more space per kilogram: 10 kg of vegetable oil at 0.92 kg/L fills 2.87 gallons, more room than 10 kg of water would need. Dense honey goes the other way — 20 kg squeezes into just 3.72 gallons. For anything not in the list, find its density and divide the same way.
How it’s calculated
Liters = kg ÷ density (kg/L, numerically equal to g/mL); US gallons = liters ÷ 3.785411784 (exact NIST gallon). Densities used: water 1.00, whole milk 1.03, vegetable oil 0.92, all-purpose flour 0.53, granulated sugar 0.85, honey 1.42, butter 0.955.
Densities are approximate and drift with temperature — hot water, warm honey, and packed versus loose flour all shift the true volume a few percent.
What 20 kg fills, by substance
| Substance | Density (kg/L) | 20 kg in US gallons |
|---|---|---|
| Water | 1.00 | 5.28 gal |
| Whole milk | 1.03 | 5.13 gal |
| Vegetable oil | 0.92 | 5.74 gal |
| All-purpose flour | 0.53 | 9.97 gal |
| Granulated sugar | 0.85 | 6.22 gal |
| Honey | 1.42 | 3.72 gal |
| Butter | 0.955 | 5.53 gal |
Gallons = 20 ÷ density ÷ 3.785411784; densities are approximate typical values.
Common mistakes
- Using 4 liters per gallon as a shortcut — the true 3.785 L makes a 5.7 percent difference on big tanks.
- Skipping density and treating every liquid like water; flour needs nearly twice the space per kg.
- Converting into imperial gallons (4.546 L) with the US factor, or vice versa.
- Assuming a substance's bagged weight fills the same volume once settled — powders compact in transit.
Frequently asked questions
How do I convert kg to gallons?
Divide kilograms by the density in kg/L to get liters, then divide by 3.785411784 for US gallons. For 20 kg of water: 20 ÷ 1.00 ÷ 3.7854 = 5.28 gallons.
How many kg is 1 gallon of water?
About 3.79 kg, because a US gallon is 3.785 liters and water weighs close to 1 kg per liter. A 5-gallon jug of water is therefore roughly 18.9 kg, or 41.7 lb.
Why do I need to pick a substance?
Because kilograms are weight and gallons are volume. The same 20 kg fills 5.28 gallons as water but 9.97 gallons as flour — density is the bridge, and it differs per substance.
Does this work for UK gallons?
Not directly. An imperial gallon is 4.54609 liters, so divide liters by 4.54609 instead. Twenty kg of water is 4.4 imperial gallons versus 5.28 US gallons.