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Gallons to Liters (US) (gal to L)
Convert gallon (us)s to liters instantly. The formula is liters = gallons × 3.78541 — one US gallon is 3.78541 liters — fuel economy and aquarium volumes use it daily. Everything is computed locally in your browser; nothing is uploaded.
How to convert gal to L
The exact conversion factor between gallon (us)s and liters gives the formula liters = gallons × 3.78541. One US gallon is 3.78541 liters — fuel economy and aquarium volumes use it daily.
For a rough mental estimate, remember that 1 gal = 3.79 L. To go the other way, see the liters to gallons (us) converter — it uses the reciprocal factor.
Worked examples
Example: convert 5 gal to L. Apply the formula — liters = gallons × 3.78541 — and you get 18.93 L. Reverse-check it by using the liters to gallons (us) to come back to 5 gal; if you do not land on the original number, a factor was inverted.
Example: convert 55 gal to L. Apply the formula — liters = gallons × 3.78541 — and you get 208.2 L. Reverse-check it by using the liters to gallons (us) to come back to 55 gal; if you do not land on the original number, a factor was inverted.
Where the factor comes from
The US fluid ounce, cup, pint, quart and gallon form one coherent system: 1 US gallon is exactly 231 cubic inches, and everything else divides from it. That is why the US fluid ounce is 29.5735 ml — an awkward number with a precise origin. The imperial (UK) system redefines all of them, so a UK pint (568 ml) is 20% larger than a US pint (473 ml). Always check which system a recipe or a product label uses before converting.Common mistakes
US vs imperial ounces. A UK imperial fluid ounce is 28.413 ml, a US one 29.5735 ml. Labels from the UK, Canada (pre-1970s recipes) and the US are not interchangeable.
Dry vs liquid measures. US dry ounces measure weight, liquid ounces measure volume. "8 oz" on a cheese label is weight; "8 fl oz" on a carton is volume — they are not the same cup.
Quart/pint arithmetic across systems. In the US system, 2 cups = 1 pint, 2 pints = 1 quart. Imperial pints contain 20 fl oz, not 16 — importing the 2-cup rule gives wrong results.
Quick mental shortcuts
Mental shortcuts: ml → cups ≈ ÷240 (close to the exact 236.588); fl oz → ml ≈ ×30; a liter is a quart plus 5% (1 L = 33.8 fl oz, 1 US quart = 32 fl oz).
Common gal to L conversions
| Gallon (US) (gal) | Liter (L) |
|---|---|
| 1 | 3.79 |
| 5 | 18.93 |
| 10 | 37.85 |
| 15 | 56.78 |
| 55 | 208.2 |
FAQ
How do I convert gal to L?
liters = gallons × 3.78541. One US gallon is 3.78541 liters — fuel economy and aquarium volumes use it daily.
What is 5 gal in L?
5 gal equals 18.93 L. Use the converter above for any value.
How do I convert L back to gal?
Use the reverse conversion — see our liters to gallons (us) converter. The calculator above also shows the reciprocal rate.
Is the gal-to-L conversion exact?
Yes — modern units are defined by international agreement with exact factors (e.g. 1 inch = 2.54 cm exactly). Results are rounded only for display.
More conversions
cm → inin → cmmm → inin → mmm → ftft → mkm → mimi → kmkg → lblb → kgg → ozoz → g°C → °F°F → °CL → galg → cupcup → gg → tbsptbsp → gg → mlml → gml → cupcup → mlfl oz → mlml → fl oz
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