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Gallons to Fluid Ounces Converter

Convert gallons to fluid ounces using the formula gal × 128 = fl oz. The calculator below shows higher precision results. The reference table is rounded for readability.

This converter uses US customary gallons and fluid ounces. UK (imperial) gallons and fluid ounces are a different size.

gal
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128 fl oz
gal × 128 = fl oz
gal to fl oz formula and worked examples

Formula and Step-by-Step

gal × 128 = fl oz

Step-by-step: 1 gal to fl oz

  1. Start with 1 gal
  2. Multiply by 128: 1 × 128 = 128
  3. Result: 1 gal = 128 fl oz

Conversion Table

Common gallons to fluid ounces values. The table and calculator both use the same conversion formula shown above.

What Are Gallons and Fluid Ounces?

What is a Gallon?

A US gallon is a unit of volume equal to approximately 3.785 liters. Note: a UK (imperial) gallon is larger at 4.546 liters. This converter uses US gallons.

What is a Fluid Ounce?

A US fluid ounce is a unit of volume equal to approximately 29.57 milliliters. A UK (imperial) fluid ounce is slightly smaller at 28.41 milliliters. This converter uses US fluid ounces.

Why convert gallons to fluid ounces?

People convert gallons to fluid ounces when working across different measurement systems.

Frequently Asked Questions

1 US gallon equals 128 fluid ounces.
The formula is: gal × 128 = fl oz. See the gal to fl oz formula page for step-by-step worked examples.
Use the fluid ounces to gallons converter. 1 fl oz = 0.007813 gal.
Yes. The conversion uses the formula gal × 128 = fl oz, which is the exact internationally defined standard. Table values are rounded for quick reference.
Apply the formula gal × 128 = fl oz. For quick estimates, round the factor to a simpler number.