Convert US fluid ounces to Imperial gallons with confidence.
1 fl oz ÷ 153.722 = 0.007 gal
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Ever tried following a British recipe only to realize it uses Imperial gallons instead of cups? Or maybe you’re comparing fuel efficiency ratings between American and European cars? Converting US fluid ounces to Imperial gallons isn’t just about numbers—it’s about bridging measurement cultures. Let’s simplify this for you.
Unit definitions
What is a US fluid ounce (fl oz)?
- Description: The smallest liquid unit in the US customary system.
- Symbol: fl oz
- Common uses: Beverage sizes, cooking measurements, perfume bottles.
- Definition: 1/128th of a US liquid gallon, equivalent to 29.5735 milliliters.
What is an Imperial gallon (gal)?
- Description: A large volume unit in the British Imperial system.
- Symbol: gal
- Common uses: Fuel economy in the UK, large liquid quantities.
- Definition: 4.54609 liters, originally based on 10 pounds of water at 62°F.
Conversion formula
To convert US fluid ounces to Imperial gallons:
Imperial gallons = US fluid ounces ÷ 153.72159
For rough estimates, divide by 154. You’ll be within 0.2% of the actual value.
Example calculations
- Converting 50 US fl oz to Imperial gallons:
50 ÷ 153.72159 ≈ 0.325 Imperial gallons
(That’s roughly 1/3 of an Imperial gallon—imagine a large milk carton.) - Converting 250 US fl oz to Imperial gallons:
250 ÷ 153.72159 ≈ 1.626 Imperial gallons
(Enough to fill a small aquarium tank.)
Conversion tables
US fluid ounces to Imperial gallons
| US fl oz | Imperial gal |
|---|---|
| 10 | 0.065 |
| 50 | 0.325 |
| 100 | 0.650 |
| 150 | 0.975 |
| 200 | 1.300 |
| 250 | 1.626 |
| 500 | 3.252 |
| 750 | 4.878 |
| 1000 | 6.504 |
Imperial gallons to US fluid ounces
| Imperial gal | US fl oz |
|---|---|
| 0.5 | 76.86 |
| 1 | 153.72 |
| 2 | 307.44 |
| 5 | 768.61 |
| 10 | 1537.22 |
Historical background
The Imperial gallon’s story begins in 1824 when the Britsh Weights and Measures Act standardized volume measurements across the Empire. Unlike the US gallon rooted in colonial-era wine trade, the Imperial gallon was designed around water’s properties—specifically, the volume occupied by 10 pounds of water at 62°F. This difference explains why 1 Imperial gallon equals 1.20095 US gallons today. During World War II, this measurement divide even affected Allied supply logistics when converting fuel quantities.
Interesting facts
- Fuel economy quirk: A car rated 30 miles per Imperial gallon gets about 25 miles per US gallon.
- Canadian transition: Canada officially switched to liters in 1970 but still uses Imperial gallons for some agricultural products.
- Beer legacy: UK pub glasses are sized in Imperial pints (20 fl oz), 25% larger than US pints.
- Space oddity: NASA uses metric units but occasionally converts historical data from Imperial gallons.
- Beverage math: A standard US beer keg (1984 fl oz) equals ~12.9 Imperial gallons.
FAQ
They originated from separate historical standards—the US gallon from wine trade measurements, the Imperial gallon from 1824 British reforms based on water volume.
153.722 US fl oz equal 1 Imperial gallon. Use our converter above for quick results.
Yes, but double-check measurements since even small errors affect baking outcomes.
No. One Imperial fluid ounce equals about 0.96076 US fluid ounces.
Mainly the UK, Canada (partially), and some Caribbean nations. Most others use liters.