Volume / imp gal → US fl oz
Convert Imperial gallons to US fluid ounces
Convert liters, milliliters, cubic meters, and clearly labeled US and imperial measures for liquids and capacity. Convert Imperial gallons (imp gal) to US fluid ounces (US fl oz). Find the formula, worked examples, unit definitions, and practical guidance below.
Reverse: US fluid ounces to Imperial gallons →
How to convert imperial gallons to US fluid ounces
US customary, imperial, and metric kitchen measures can have different sizes despite similar names. Use the system printed on your recipe or container.
Use x for the value in imp gal, b for the intermediate value in L, and y for the result in US fl oz.
US fl oz = imp gal × 4.54609 ÷ 0.0295735295625
Worked examples
10 imp gal ≈ 1537.21590465 US fl oz
Step 1: (10 × 4.54609) ≈ 45.4609 L.
Step 2: 45.4609 ÷ 0.0295735295625 ≈ 1537.21590465 US fl oz.20 imp gal ≈ 3074.43180929 US fl oz
Step 1: (20 × 4.54609) ≈ 90.9218 L.
Step 2: 90.9218 ÷ 0.0295735295625 ≈ 3074.43180929 US fl oz.
Results are rounded to 12 significant digits. Converting units does not increase the precision of the original measurement. Very large or small values outside JavaScript’s finite numeric range are rejected.
About Imperial gallons
An imperial gallon is exactly 4.54609 liters. Its capacity is greater than a US liquid gallon, so labels that only say “gallons” need a system check.
About US fluid ounces
A US fluid ounce is one 128th of a US liquid gallon. It measures volume and is different from an imperial fluid ounce or an ounce of mass.
Definitions and sources
Check which gallon, cup, or ounce you mean
A US liquid gallon contains 3.785411784 liters; an imperial gallon contains 4.54609 liters. This calculator labels both explicitly and does not substitute one for the other.
Our US customary cup is 236.5882365 mL. A recipe may instead use a 250 mL metric cup or a 240 mL cup. Fluid ounces measure volume, while ounces in the Weight category measure mass.
For a tank or room, calculate the volume using dimensions in the same length unit before converting its cubic units. Changing only one side’s unit will give an incorrect volume.
Check the cup or fluid-ounce convention before using a converted volume in recipe calculations.
Imperial gallons to US fluid ounces reference table
| Imperial gallons (imp gal) | US fluid ounces (US fl oz) |
|---|---|
| 1 | 153.721590465 |
| 5 | 768.607952323 |
| 10 | 1537.21590465 |
| 25 | 3843.03976162 |
| 50 | 7686.07952323 |
| 100 | 15372.1590465 |
| 1000 | 153721.590465 |
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