21 US gallons to liters
79.49 L
21 gal = 79.49 L.
liters
79.49L
21 gal = 79.49 L
The short answer
How many liters is 21 US gallons?
21 gal = 79.49 L. 1 US gallon = 3.785412 liters, so the working is 21 × 3.785412 = 79.49.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 US gallon = 3.785412 liters 21 × 3.785412 = 79.49
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (L) | Off by |
|---|---|---|
| Whole number | 79 | −0.49365 |
| 1 decimal | 79.5 | +0.00635 |
| 2 decimals | 79.49 | −0.00365 |
Round trip: take 79.49 L back the other way and you land on 20.9990 gal — a drift of 0.0010 gal. That gap is the rounding, not the conversion.
What 21 gal looks like
20 gal
Twenty gallons is one of Aqueon's standard glass tank sizes, sold in both a High and a Long shape.
Frequently asked questions
What is 21 US gallons in liters?
21 US gallons is 79.49 liters. 1 US gallon = 3.785412 liters, so the working is 21 × 3.785412 = 79.49.
How accurate is 79.49 L?
Rounding to 79.49 L and converting straight back gives 20.9990 gal, a drift of 0.0010 gal from the 21 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
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