How many gallon are in a kg?

Quick Answer

There are approximately 0.26417 gallons in 1 kilogram of water. This conversion is based on the density of water, which is 1 kg per liter. Since there are 3.78541 liters in a US gallon, 1 kg of water is equivalent to 0.26417 gallons.

How to Convert Kilograms to Gallons

To convert kilograms to gallons, we need to use the density of water along with the conversion between liters and gallons. Here are the steps:

  1. Find the density of water in kg/L. The density of water is 1 kg per liter.
  2. Use the density to find how many liters are in 1 kg. Since the density is 1 kg/L, there are 1 liter in 1 kg.
  3. Convert liters to gallons. There are 3.78541 liters in 1 US gallon.
  4. Use the liter to gallon conversion to calculate how many gallons are in 1 kg. Since there are 1 L in 1 kg, and 3.78541 L per gallon, there are 3.78541/1 = 0.26417 gallons in 1 kg.

So in summary, we use the density of water to relate kilograms to liters, then convert liters to gallons to end up with 0.26417 gallons per kilogram.

Density of Water

The density of water is a key factor in relating kilograms to gallons. Density is defined as mass per unit volume. For water, the density is:

  • 1 kg per liter
  • 1 g per cm3
  • 62.43 lbs per ft3

The SI unit for density is kg/m3. But for water, we commonly use the density of 1 kg/L or 1 g/mL. This tells us the mass of a given volume of water.

At standard temperature and pressure (25°C and 1 atm), 1 liter of water has a mass of 1 kilogram. This allows us to relate any mass of water in kg to a volume in liters, since the density is constant.

Converting Liters to Gallons

To complete the conversion from kg to gallons, we need to know how liters and gallons are related:

  • 1 US gallon = 3.78541 liters
  • 1 liter = 0.26417 gallons

The US customary unit for volume is the gallon, while the metric system uses the liter. Since the density of water is expressed in kg/L, we need to convert the liters to gallons to end up with a mass-to-volume relationship in the desired units.

Metric Conversions

1 liter (L) = 1000 milliliters (mL)
1 L = 1000 cubic centimeters (cm3)

Some other useful metric conversions:

  • 1000 L = 1 cubic meter (m3)
  • 100 centiliters (cL) = 1 deciliter (dL) = 0.1 L
  • 10 milliliters (mL) = 1 centiliter (cL)

US Customary Conversions

1 gallon (gal) = 4 quarts (qt)
1 qt = 2 pints (pt)
1 pt = 2 cups (c)
1 c = 8 fluid ounces (fl oz)

Some other useful US customary conversions:

  • 1 gallon = 128 fluid ounces
  • 1 quart = 32 fluid ounces
  • 1 pint = 16 fluid ounces
  • 1 cup = 8 fluid ounces

Kilograms to Gallons Formula

Using the density of water and the liter to gallon conversion, we can derive a formula to convert kg to gallons:

Gallons = Kilograms x (Liters/Kilogram) x (Gallons/Liter)

Plugging in the density of water and the conversion factors:

Gallons = Kilograms x (1 L/1 kg) x (0.26417 gal/1 L)

This simplifies to:

Gallons = 0.26417 x Kilograms

So to convert kilograms to gallons, we simply multiply the kg value by 0.26417.

Let’s look at some examples:

  • 10 kg x 0.26417 gal/kg = 2.6417 gallons
  • 25 kg x 0.26417 gal/kg = 6.604 gallons
  • 50 kg x 0.26417 gal/kg = 13.209 gallons

This simple formula allows us to easily convert between kilograms of water and gallons based on the density.

Kilograms to Gallons Conversion Table

Here is a conversion table showing some common kg to gallon conversions:

Kilograms Gallons
1 kg 0.26417 gal
5 kg 1.3209 gal
10 kg 2.6417 gal
25 kg 6.604 gal
50 kg 13.209 gal
100 kg 26.417 gal
250 kg 66.043 gal
500 kg 132.09 gal

This table makes it easy to quickly convert between kilograms and gallons for common water masses. Just look up the kg value to find the corresponding gallons.

When to Use This Conversion

Converting kilograms to gallons is useful any time you need to relate a mass of water in metric units to US customary volume units. Here are some examples of when you would need to convert kg to gal:

  • Looking up how much a certain mass of water is in gallons
  • Converting the capacity of a water tank or container from kg to gallons
  • Calculating the number of gallons needed to reach a desired mass of water in kg
  • Converting a water flow rate given in kg/s to gal/min
  • Finding the number of gallons in a certain mass of ice given in kg and converting to liquid water
  • Relating a dosage or recipe amount given in kg of water to gallons
  • Converting the mass of water-based liquids like juices, soups, etc. from kg to gallons

Any application involving mass of water in kg and volume needed in gallons requires converting between these units using the density of water.

Gallons to Kilograms Conversion

We can also convert gallons back to kilograms using the density of water. The formula is:

Kilograms = Gallons x (Liters/Gallon) x (Kilograms/Liter)

Plugging in the conversion factors:

Kilograms = Gallons x (3.78541 L/1 gal) x (1 kg/1 L)

This simplifies to:

Kilograms = 3.78541 x Gallons

To convert gallons to kg, we multiply the gallons by 3.78541.

Let’s look at some examples converting gallons to kilograms:

  • 5 gal x 3.78541 kg/gal = 18.927 kg
  • 10 gal x 3.78541 kg/gal = 37.854 kg
  • 25 gal x 3.78541 kg/gal = 94.635 kg
  • 50 gal x 3.78541 kg/gal = 189.271 kg

Using this quick gallon-to-kilogram calculation allows easy conversion from US customary volume units to metric mass units for water.

Gallons to Kilograms Conversion Table

Here is a conversion table showing some common gallon to kg conversions:

Gallons Kilograms
1 gal 3.78541 kg
5 gal 18.927 kg
10 gal 37.854 kg
25 gal 94.635 kg
50 gal 189.271 kg
100 gal 378.541 kg
250 gal 946.353 kg

This table allows easy conversion from gallons to kilograms for common water volumes. Just lookup the gallons value to find the equivalent kg.

When to Convert Gallons to Kilograms

Converting gallons to kilograms is useful when you need to go from a US customary volume to a metric mass, including:

  • Calculating the mass in kg of a given volume of water in gallons
  • Converting the capacity of a tank or container from gallons to kg
  • Determining the mass of water in kg that corresponds to a certain number of gallons
  • Converting a water flow rate from gal/min to kg/s
  • Finding the equivalent mass in kg of a volume of ice water given in gallons
  • Converting a water amount for a dosage, recipe, mixture, etc. from gallons to kilograms

Any application involving gallons of water that needs to be converted to mass units in kg can use this simple gallons to kg calculation.

Converting Other Units

The conversions between kilograms, liters, and gallons can also be extended to other units like pounds, ounces, fluid ounces, cubic inches, etc.

For example, to convert between pounds and gallons, we would use the density of water:

  • Density of water = 8.345 lbs/gal
  • 1 gallon = 8.345 pounds

Some other unit conversions for water:

From To Conversion Factor
kg lb 1 kg = 2.20462 lb
lb kg 1 lb = 0.45359 kg
L fl oz 1 L = 33.814 fl oz
fl oz L 1 fl oz = 0.02957 L
mL in3 1 mL = 0.06102 in3
gal in3 1 gal = 231 in3

This allows conversion between other common mass and volume units using the underlying liter and gallon conversions.


While very useful, there are some limitations when converting between kilograms and gallons:

  • Only applies to pure water. Other liquids will have different densities.
  • Assumes standard conditions (25°C and 1 atm pressure) where density = 1 kg/L.
  • Does not account for the volume of dissolved substances.
  • Does not apply to slurries, suspensions, etc. where water has solids added.
  • Rounded conversions lose a bit of accuracy. More precise values can be used.
  • Does not work for conversions involving non-volumetric masses like kilograms of apples, sugar, etc.

Within these limitations, the conversions are an easy way to relate a mass of pure water in kg to a volume in gallons or other units. Just be aware it only applies strictly to water.


To summarize, there are 0.26417 gallons in 1 kilogram of water based on the density of water being 1 kg/L. We can easily convert between kilograms and gallons by:

  • Kilograms x 0.26417 = Gallons
  • Gallons x 3.78541 = Kilograms

These conversions allow relating mass and volume units for water measurements using the constant density. Converting between kg and gal is useful any time you need to calculate a volume in gallons for a given mass in kg or vice versa. Just multiply by the appropriate conversion factor.

Other units like pounds, fluid ounces, etc. can also be interconverted using the density and conversions between liters and gallons. This provides a handy way to translate between metric and US customary units when working with water.

So in summary, about 0.26 gallons per 1 kg of water – a simple fact that can greatly simplify water measurements and conversions!

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