Kilograms to Gallons Converter
Convert kg to UK imperial gallons for water, petrol, milk, and more
Popular Conversions
Common kilogram to UK imperial gallon conversions for frequently measured substances.
| Kilograms (kg) | Water (gal) | Petrol (gal) | Milk (gal) | Diesel (gal) |
|---|---|---|---|---|
| 1 kg | 0.220 gal | 0.299 gal | 0.214 gal | 0.259 gal |
| 5 kg | 1.100 gal | 1.493 gal | 1.068 gal | 1.294 gal |
| 10 kg | 2.200 gal | 2.986 gal | 2.136 gal | 2.588 gal |
| 20 kg | 4.399 gal | 5.972 gal | 4.271 gal | 5.175 gal |
| 50 kg | 10.998 gal | 14.931 gal | 10.679 gal | 12.938 gal |
| 100 kg | 21.997 gal | 29.862 gal | 21.357 gal | 25.877 gal |
Conversion Formula and Method
Converting kilograms to UK imperial gallons requires knowledge of the substance’s density, as kilograms measure mass whilst gallons measure volume. The relationship between these units depends on the material being converted.
Imperial Gallons = Kilograms ÷ (Density × 4.546)
Where density is measured in g/mL and 4.546 is the number of litres in one UK imperial gallon.
Step-by-Step Conversion Process
Step 1: Identify Density
Determine the density of your substance in grams per millilitre (g/mL). Water has a density of 1.0 g/mL, whilst petrol is approximately 0.737 g/mL.
Step 2: Apply Formula
Divide your kilogram value by the product of the density and 4.546 (litres per imperial gallon).
Step 3: Verify Result
Check that your result makes logical sense. Lighter substances (lower density) will produce larger gallon values for the same mass.
Worked Example
Converting 25 kg of petrol to imperial gallons:
Given: Mass = 25 kg, Density of petrol = 0.737 g/mL
Conversion: 25 ÷ (0.737 × 4.546) = 25 ÷ 3.350 = 7.46 imperial gallons
Result: 25 kg of petrol equals approximately 7.46 UK imperial gallons
Imperial vs US Gallons
The UK imperial gallon differs significantly from the US gallon, which is crucial when converting measurements. The imperial gallon is approximately 20% larger than its American counterpart.
Volume Comparison
1 UK imperial gallon = 1.201 US gallons
This difference stems from historical measurement standardisation. The imperial system, adopted in 1824, defined the gallon as 10 pounds of water at 62°F (277.42 cubic inches). The US retained an earlier definition based on 231 cubic inches, resulting in the smaller US gallon still in use today.
Substance Density Reference
Different substances have varying densities, which directly affects kg to gallon conversions. Below are common densities at room temperature (20°C).
| Substance | Density (g/mL) | 1 kg = Imperial Gallons |
|---|---|---|
| Water | 1.000 | 0.220 gal |
| Petrol (Unleaded) | 0.737 | 0.299 gal |
| Diesel | 0.850 | 0.259 gal |
| Milk (Whole) | 1.030 | 0.214 gal |
| Olive Oil | 0.918 | 0.240 gal |
| Vegetable Oil | 0.880 | 0.250 gal |
| Honey | 1.420 | 0.155 gal |
| Sea Water | 1.030 | 0.214 gal |
| Ethanol | 0.789 | 0.279 gal |
| Glycerine | 1.260 | 0.175 gal |
Frequently Asked Questions
How many gallons are in 1 kilogram?
The number of gallons in 1 kilogram depends entirely on the substance’s density. For water, 1 kg equals approximately 0.220 UK imperial gallons. For petrol, 1 kg equals approximately 0.299 imperial gallons due to petrol’s lower density. You must know the specific substance to perform an accurate conversion.
What is the difference between UK and US gallons?
A UK imperial gallon contains 4.546 litres, whilst a US gallon contains only 3.785 litres. This makes the imperial gallon approximately 20% larger. When converting kilograms to gallons, always specify which gallon type you require, as the results differ significantly. This converter uses UK imperial gallons throughout.
Why do I need to know the density for kg to gallon conversion?
Kilograms measure mass (how much matter something contains), whilst gallons measure volume (how much space something occupies). The same mass of different substances occupies different volumes depending on density. For example, 10 kg of honey occupies less volume than 10 kg of petrol because honey is denser.
How do I convert kg of fuel to gallons for my vehicle?
For petrol (unleaded), divide your kilogram value by 3.350 to get imperial gallons. For diesel, divide by 3.864. Alternatively, use the converter above and select the appropriate fuel type. Remember that fuel stations in the UK dispense in litres, so you may need to convert further (1 imperial gallon = 4.546 litres).
Can I convert kg to gallons without knowing the substance?
No, an accurate conversion is impossible without knowing the substance’s density. If you only have mass in kilograms, you must either identify the material or measure its density. Some substances have variable densities depending on temperature or composition, which can affect precision.
What if my substance isn’t listed in the dropdown menu?
Select “Custom Density” from the dropdown menu, then enter your substance’s density in grams per millilitre (g/mL). You can find density values in reference materials, product specifications, or by measuring the substance’s mass and volume directly.
How accurate are these conversions?
The conversions are mathematically precise based on the density values provided. However, real-world accuracy depends on several factors: temperature affects density, substances may have impurities, and measurement precision varies. For critical applications requiring exact measurements, verify the actual density under your specific conditions.
Why does petrol weigh less than water per gallon?
Petrol has a lower density (approximately 0.737 g/mL) compared to water (1.0 g/mL). This means petrol molecules are less tightly packed together than water molecules. Consequently, one imperial gallon of petrol weighs about 3.35 kg, whilst one imperial gallon of water weighs 4.546 kg.