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US gallons to millilitres

Multiply US gallons by 3,785.4118 to get millilitres.

1 gal = 3,785.4118 mLNIST HB 44 · BIPM SI
gal
11,356.2354mL

3 gal = 11,356.2354 mL

How to convert US gallons to millilitres

The millilitre is one thousandth of a litre, equal to one cubic centimetre (cm³). The US gallon is the US liquid gallon, exactly 231 cubic inches (3.785411784 litres).

Worked example — 3 gal: 3 × 3,785.4118 = 11,356.2354 mL.

US gallons to millilitres table

Common conversions. The reverse table is on millilitres to US gallons.
US gallonsMillilitres
0.25 gal946.3529 mL
0.5 gal1,892.7059 mL
1 gal3,785.4118 mL
2 gal7,570.8236 mL
3 gal11,356.2354 mL
5 gal18,927.0589 mL
10 gal37,854.1178 mL
15 gal56,781.1768 mL
20 gal75,708.2357 mL

Reverse and related

About US gallons and millilitres

US gallon (gal)

1 gal = 3,785.4118 mL

Definition. The US liquid gallon, exactly 231 cubic inches (3.785411784 litres)

History and origin

The US gallon derives from the old English wine gallon of 231 cubic inches, a value the United States kept when Britain moved to a larger imperial gallon in 1824. It equals exactly 3.785411784 litres.

Current use

The gallon is the everyday US unit for fuel, milk and paint; the imperial gallon used in the UK and Canada is about 20 percent larger.

Source: NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents)

Millilitre (mL)

1 mL = 0.000264172 gal

Definition. One thousandth of a litre, equal to one cubic centimetre (cm³)

History and origin

The millilitre is one thousandth of a litre, equal to one cubic centimetre. It came with the decimal metric system as the unit for small liquid volumes.

Current use

Millilitres are used for recipes, medicine doses and cosmetics, and are printed on most small bottles and cans.

Source: BIPM SI Brochure (2019); the litre is an SI-accepted unit (1 L = 1 dm³)

Where people use this

US gallons: fuel in the US, large containers, paint. Millilitres: recipes, medicine doses, cosmetics. 1 US gallon is about 3785 mL.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 mL = 0.0002641720524 gal, so 1 gal = 1 ÷ 0.0002641720524 = 3,785.4118 mL.

Every value is carried to full double precision; the display is rounded.

Sources: BIPM SI Brochure (2019); the litre is an SI-accepted unit (1 L = 1 dm³); NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents).

Questions people ask

How many mL in a US gallon?

One US gallon is about 3785 mL.

How many mL is half a gallon?

Half a US gallon is about 1893 mL.

How many mL is 2 gallons?

2 US gallons is about 7571 mL.

All US gallon conversions