You can use oz to gallon calculator below or do the calculation by your self with the conversion factor .

The conversion of the fluid Oz to gallon differ from the British imperial system and the US :

- 1 Ounce [Liquid OZ, US Customary Units] = 0.0078125 (1/128) Gallon [liquid, US Customary Units].
- 1 Ounce [Liquid OZ, UK British Imperial System] = 0.00625 (1/160) Gallon [liquid, UK British Imperial System].

A fluid Ounce (OZ) is unit of volume also called capacity is almost equal to 28.4130625 millilitres (28ml) in the British imperial system. Therefore a fluid ounce (OZ) is consequently equal to 29.5735295625 milliliters (30ml) in the US Customary Units.

**Note:** Most of all the US regulation defines the liquid ounce as exactly 30 milliliters as per 21 CFR 101.9 but this is for the labeling only.

**Examples:**

### oz to gallon calculator the US Customary Units example:

**Task 1:** Convert *64 US fluid ounces to US gallons.*

**Equation:**

fl OZ / 128= gallon.

**Calculation:**

64 fl OZ / 128= 0.5 gallon.

**Result:**

64 US fl oz is equivalent to 0.5 gallon.

### oz to gallon calculator the British imperial system example:

**Task 2:** Convert *64 *British imperial system.

**Equation :**

fl OZ /160= gallon.

**Calculation : **

64 fl OZ / 160= 0.4 gallon.

**Result : **64 US fl oz is equivalent to 0.4 gallon.

**Conversion table :**

**Conversion table** US Customary Units

OZ. | Gallon |

128 OZ. | 1 gallon. |

64 OZ. | 1/2 gallon. |

32 OZ. | 1/4 gallon. |

16 OZ. | 1/8 gallon. |

8 OZ. | 1/16 gallon. |

### Conversion table British Imperial System

OZ. | Gallon. |

160 OZ. | 1 gallon. |

80 OZ. | 1/2 gallon |

40 OZ. | 1/4 gallon. |

20 OZ. | 1/8 gallon. |

10 OZ | 1/16 gallon. |

History of once as well-written in wikipedia:

“”The fluid ounce was originally the volume occupied by one ounce of some substance such as wine (in England) or water (in Scotland).The most importantly the ounce in question varied depending on the system of fluid measure, such as that used for wine versus ale.””

History of once

For further definitions about fluid ounce and gallon check the below links: