Put 42 US gallons into the exact factor of 3.785411784 and you get 158.9872949 L. Written out: 42 × 3.785411784 = 158.987294928 liters, with no rounding applied until the final display.
158.987 litres is 42 US gallons and 34.97 imperial gallons. In a car averaging 7 L/100 km it is about 2271 km of range; as drinking water at the 2 litres a day figure, 79.5 days.
The result sits 1.013 L short of 160 L, so if you need a round figure to quote, 160 L is the honest nearest one. Plenty of people do this in their head: multiply by 3.8 instead of using the exact factor 3.785411784. At 42 that shortcut gives 159.6 liters, off by 0.6127 liters or about 0.39%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
The formula
42 gal- The quantity being converted
3.785411784- Exact liters in one US gallon
158.9872949 L- The converted result
How it works, step by step
- Take the US gallon value, 42.
- Multiply by 3.785411784, the exact number of liters in one US gallon.
- That gives 158.987294928 liters.
- To reverse it, divide by 3.785411784 instead: 158.9872949 L ÷ 3.785411784 returns 42 gal.
Worked examples
Working it through
42 gal × 3.785411784 = 158.987294928 L. One multiplication, with no rounding until the value reaches the screen.
Verifying the result
Run it in reverse — 158.9872949 L ÷ 3.785411784 = 42 gal. Matching the input you started from is the proof the direction is right.
How to read your score
Frequently asked questions
What is 42 US gallons in liters?
42 US gallons is exactly 158.9872949 L. Carried to full precision that is 158.987294928 liters.
How do you convert US gallons to liters?
Multiply by 3.785411784. So 42 × 3.785411784 = 158.9872949 liters. The factor comes from a definition rather than a measurement, so it never changes.
What is 158.9872949 liters back in US gallons?
42 US gallons. Dividing by 3.785411784 undoes the conversion exactly.
What does 42 gal actually look like?
158.987 litres is 42 US gallons and 34.97 imperial gallons. In a car averaging 7 L/100 km it is about 2271 km of range; as drinking water at the 2 litres a day figure, 79.5 days. Compare it against the surrounding values in the table below.
What is an US gallon?
Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
What is a liter?
One cubic decimetre — the everyday metric unit for drinks and fuel.
42 gal in liters — nearby values
| Us Gallons | Liters | Unrounded |
|---|---|---|
| 36 gal | 136.27482 | 136.2748242 |
| 37 gal | 140.06024 | 140.060236 |
| 38 gal | 143.84565 | 143.8456478 |
| 39 gal | 147.63106 | 147.6310596 |
| 40 gal | 151.41647 | 151.4164714 |
| 41 gal | 155.20188 | 155.2018831 |
| 42 gal | 158.98729 | 158.9872949 |
| 43 gal | 162.77271 | 162.7727067 |
| 44 gal | 166.55812 | 166.5581185 |
| 45 gal | 170.34353 | 170.3435303 |
| 46 gal | 174.12894 | 174.1289421 |
| 47 gal | 177.91435 | 177.9143538 |
| 48 gal | 181.69977 | 181.6997656 |
Exact factor: 1 US gallon = 3.785411784 liters. The row for 42 gal is the value this page is about.