Convert US gallons to US fluid ounces instantly. Both are US customary units, and the relationship is exact: there are 128 US fluid ounces in every US gallon, so to go from US gallons (gal) to US fluid ounces (fl oz) you multiply by 128 — for example, 1 gal = 128 fl oz and 0.5 gal = 64 fl oz. This converter defaults to…
1 US gallon = 128 US fluid ounce · 1 US gallon = 128 US fluid ounce
METRIC
US CUSTOMARY
IMPERIAL / UK
SPOONS & COOKING MEASURES
Enter the volume in US gallons (gal) in the value box — the converter defaults to US gallons → US fluid ounces.
Read the US fluid ounce (fl oz) result instantly, or do it by hand: multiply the gallons by 128.
Use the gallons-to-fl-oz table below for common values, or tap ⇄ to convert US fluid ounces back to US gallons.
Need another unit? Pick any of the 59 volume units in the dropdown, then Share or Embed your conversion.
1 US cup
236.6 mL
1 metric cup
250 mL
1 imp cup
284.1 mL
1 US tbsp
14.79 mL
1 US tsp
4.929 mL
1 metric tbsp
15 mL
1 AU tbsp
20 mL
1 US cup
16 US tbsp
1 US tbsp
3 US tsp
1 stick
½ US cup
Recipe measurements look simple until you notice that a “cup” or “tablespoon” means different things in different countries — which is exactly what trips cooks up. A US cup is 236.6 mL, but a metric cup (used in Australia, New Zealand and much of the world) is 250 mL, and an old imperial (UK) cup is 284 mL; US nutrition labels even use a 240 mL “legal cup”. Spoons vary too: a US tablespoon is 14.8 mL and a metric one is 15 mL — close enough to ignore — but an Australian tablespoon is 20 mL, equal to four teaspoons rather than three, which is a genuine trap when following an Aussie recipe. Fluid ounces differ as well: the US fluid ounce is 29.57 mL while the imperial one is 28.41 mL, so US and UK pints, quarts and gallons are not the same size. This converter keeps every national version separate and also handles the small “old recipe” measures — a dash is an eighth of a teaspoon, a pinch a sixteenth and a smidgen a thirty-second — plus the US stick of butter, which is half a cup or eight tablespoons. One thing it does not do is turn cups into grams: that depends on the ingredient, because a cup of flour and a cup of sugar weigh different amounts. Every unit here is stored as its exact number of millilitres, so any conversion is just the input turned into millilitres and then into the unit you want.
Multiply the number of US gallons by 128. Because there are exactly 128 US fluid ounces in a US gallon, multiplying by 128 gives the fluid-ounce value. For example, 3 gal × 128 = 384 fl oz. The converter does this instantly for any value.
Mega Volume Converter
Calculate instantly →
Milliliters to Liters
Calculate instantly →
Milliliters to US Fluid Ounces
Calculate instantly →
Milliliters to US Cups
Calculate instantly →
Milliliters to Teaspoons
Calculate instantly →
Milliliters to Tablespoons
Calculate instantly →
Liters to Milliliters
Calculate instantly →
Liters to US Fluid Ounces
Calculate instantly →
Liters to US Pints
Calculate instantly →
Liters to US Quarts
Calculate instantly →
Liters to US Gallons
Calculate instantly →
US Fluid Ounces to Milliliters
Calculate instantly →
US Fluid Ounces to Liters
Calculate instantly →
US Fluid Ounces to US Gallons
Calculate instantly →
US Cups to Milliliters
Calculate instantly →
US Pints to Liters
Calculate instantly →
US Quarts to Liters
Calculate instantly →
US Gallons to Liters
Calculate instantly →
Teaspoons to Milliliters
Calculate instantly →
Last updated: — · 30 cooking-volume units · Metric, US customary, imperial & special measures, all national cup/spoon sizes kept separate · Verified by the EagleCalculator team · Eagle-eyed accuracy for every calculation.