Gallons to Milligrams Conversion Calculator

Enter the volume in gallons below to calculate the weight in milligrams.

Results in Milligrams:
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1 gal = 3,785,411.7840007 mg
1 gal = 3,785.411784 g
1 gal = 3.785412 kg

How to Convert Gallons to Milligrams

Scales are used to measure weight

To convert a gallon measurement to a milligram measurement, multiply the volume by 3,785,411.784 times the density of the ingredient or material.

You can use this simple formula to convert:

milligrams = gallons × 3,785,411.784 × ingredient density

Thus, the volume in milligrams is equal to the gallons multiplied by 3,785,411.784 times the density of the ingredient or material.

For example, here's how to convert 5 gallons to milligrams for an ingredient with a density of 0.7 g/mL.
5 gal = 5 × 3,785,411.784 × 0.7 = 13,248,941.244 mg

Gallons and milligrams are both commonly used to measure cooking ingredients.

For cooking applications, most chefs suggest measuring dry ingredients by weight rather than volume to improve accuracy in the measurements.[1] The density of dry ingredients can vary for a variety of reasons, such as compaction.

The best way to ensure an accurate conversion is to use a scale. When a scale is not available, a calculator like the one above is a good way to estimate the volume to weight conversion.

Keep reading to learn more about each unit of measure.

How Many Milligrams are in a Gallon?

The actual weight of a gallon will vary depending on the density of the material. The table below shows how many milligrams of various wet and dry ingredients are in a gallon.

Gallon measurements converted to milligrams for commonly used ingredients.
Volume in Gallons: Weight in Milligrams of:
Water Milk Cooking Oil All Purpose Flour Granulated Sugar
1/8 gal 473,176 mg 492,104 mg 416,395 mg 250,310 mg 331,224 mg
1/4 gal 946,353 mg 984,207 mg 832,791 mg 500,621 mg 662,447 mg
1/3 gal 1,261,804 mg 1,312,276 mg 1,110,387 mg 667,494 mg 883,263 mg
1/2 gal 1,892,706 mg 1,968,414 mg 1,665,581 mg 1,001,241 mg 1,324,894 mg
2/3 gal 2,523,608 mg 2,624,552 mg 2,220,775 mg 1,334,989 mg 1,766,525 mg
3/4 gal 2,839,059 mg 2,952,621 mg 2,498,372 mg 1,501,862 mg 1,987,341 mg
1 gal 3,785,412 mg 3,936,828 mg 3,331,162 mg 2,002,483 mg 2,649,788 mg


The US liquid gallon is a unit of fluid volume equal to four quarts, eight pints, or sixteen cups.[2] The US liquid gallon should not be confused with the US dry gallon or the imperial gallon, which are different units of measure.

The gallon is a US customary unit of volume. Gallons can be abbreviated as gal; for example, 1 gallon can be written as 1 gal.


The milligram is the mass equal to 1/1,000 of a gram, or 0.0154 grains.

The milligram, or milligramme, is an SI unit of weight in the metric system. In the metric system, "milli" is the prefix for 10-3. Milligrams can be abbreviated as mg; for example, 1 milligram can be written as 1 mg.


  1. National Institute of Standards & Technology, Metric Cooking Resources,
  2. National Institute of Standards and Technology, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Handbook 44 - 2019 Edition,