Going from 10 to 20 MPG saves more fuel than going from 20 to 50.
Miles per gallon counts distance per fuel, but your tank pays for fuel per distance. That flips your intuition. Guess three swaps, then rank the real cars in your household.
Round 1 of 3
Which swap saves more fuel?
Both cars drive 10,000 miles a year. Pick the swap that burns less fuel afterwards compared with before.
Score 0 / 0
Your garage
Which upgrade is worth it?
Enter each car and what you would replace it with. Efficiency can be entered in any unit.
The curve is the whole story: fuel use is proportional to 1 divided by MPG, so the first few MPG gained cut the most. In L/100 km the same relation is a straight line, which is why the metric figure does not fool you.
Sources and constants. 1 US gallon = 3.785411784 litres exactly and 1 imperial gallon = 4.54609 litres exactly (Wikipedia: Gallon). 1 mile = 1.609344 km exactly (Wikipedia: Mile). Quiz cars are illustrative efficiency values, not specific models. Everything runs in your browser; nothing is sent anywhere.