Convert fluid ounces to US gallons

1 fl oz=0.007813gal (US)

Use the converter below to change any fluid ounces value into US gallons instantly — with formula, conversion table, and real-world examples.

You have

Equals

0.0078125

Conversion formula

Forward

US gallons = fluid ounces × 0.007813

Reverse

fluid ounces = US gallons × 128

Example: 10 fl oz × 0.007813 = 0.07813 gal (US).

About both units

From

Fluid Ounce

fl oz

The US fluid ounce equals 29.5735 millilitres — 1/128 of a US gallon. The UK fluid ounce (28.41 ml) is slightly smaller. Used for beverage can sizes in the US, cosmetic product sizes and many US cooking recipes. Do not confuse with the ounce of mass (28.35 g).

Real-world: A US soda can is 12 fl oz (355 ml). A Starbucks Tall is 12 fl oz; Grande is 16; Venti is 20.

Read full fluid ounce reference →

US Gallon

gal (US)

The US gallon equals 3.785411784 litres exactly. It is the standard fuel and liquid volume unit in the United States. A typical American car holds 14–18 US gallons of fuel. US fuel economy is quoted in miles per US gallon (mpg).

Real-world: US car tank ≈ 15 gallons (57 L). 1 US gallon of milk is a common grocery size (3.79 L). US paint often sold by the gallon.

Read full us gallon reference →

Fluid Ounce to US Gallon conversion table

Common fluid ounces to US gallons values for quick reference.

Fluid Ounce (fl oz)	US Gallon (gal (US))
1 fl oz	0.007813 gal (US)
2 fl oz	0.01563 gal (US)
5 fl oz	0.03906 gal (US)
10 fl oz	0.07813 gal (US)
20 fl oz	0.1563 gal (US)
50 fl oz	0.3906 gal (US)
100 fl oz	0.7813 gal (US)
200 fl oz	1.5625 gal (US)
500 fl oz	3.90625 gal (US)
1,000 fl oz	7.8125 gal (US)

Tips & common mistakes

Quick tips

1 US fl oz ≈ 29.6 ml; 1 UK fl oz ≈ 28.4 ml.
8 US fl oz ≈ 1 US cup ≈ 237 ml.
Use ml to avoid ambiguity between US and UK fluid ounces.

Avoid these

Mixing US and UK fluid ounces — 16 fl oz (US) = 473 ml vs. 16 fl oz (UK) = 455 ml.
Confusing fluid ounce (volume) with avoirdupois ounce (mass).
Assuming 1 fl oz = 1 oz by weight — only true for pure water and approximately.

Frequently asked questions

How many US gallons in a fluid ounce?

One fluid ounce equals 0.007813 US gallons.

How do I convert fluid ounces to US gallons?

Multiply the fluid ounce value by 0.007813 to get the equivalent in US gallons.

What is 100 fluid ounces in US gallons?

100 fluid ounces equals 0.7813 US gallons.

Is a fluid ounce bigger than a us gallon?

No. 1 fluid ounce equals 0.007813 US gallons, so one fluid ounce is smaller.

How to convert fluid ounces to US gallons without a calculator?

Multiply by 0.01 for a quick estimate; use a calculator for precise results.

Related volume conversions

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