How Many Fluid Ounces in a Gallon?

There are 128 fluid ounces in a US gallon and 160 fluid ounces in a UK (imperial) gallon.

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How many fluid ounces in a gallon? — see the answer and conversion table below.

Use the related converter below for custom values.

Formula

Answer: There are 128 fluid ounces in a US gallon and 160 fluid ounces in a UK (imperial) gallon.

Example

Question: How many fluid ounces in a gallon? Answer: There are 128 fluid ounces in a US gallon and 160 fluid ounces in a UK (imperial) gallon.

How to Use

  1. Read the direct answer at the top of the page
  2. Check the conversion table for common values
  3. Use the related converter for custom values
  4. Browse the FAQ for common follow-up questions

Frequently Asked Questions

How many 16 oz bottles in a gallon?

There are 8 bottles of 16 fl oz in 1 US gallon (128 / 16 = 8).

How many fl oz in a half gallon?

There are 64 fl oz in a half gallon (US).

How many water bottles in a gallon?

A standard 16.9 oz water bottle means about 7.57 bottles per gallon. An 8 oz bottle means 16 bottles per gallon.

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Author: Calczy Editorial Team Reviewed by: Calczy Editorial Team Last updated: 2026-10-09

This page was reviewed for accuracy by the Calczy editorial team. Our editorial process follows our editorial policy to ensure reliable, up-to-date conversion tools and reference content.