Drag force calculator
Drag goes as the square of speed and the power to overcome it as the cube, which is why top speed is so expensive.
m2
kg/m3
Drag force
363.825N
- Power to overcome it
- 10 914.75
- Same power
- 14.637 hp
- Drag area CdA
- 0.6600 m2
- Power at twice the speed
- 87 318
Show the working
- Drag coefficient = 0.3
- Frontal area = 2.2
- Air density = 1.225
- Speed = 30
- Drag force = 0.5 * 1.225 * 0.3 * 2.2 * 30^2 = 363.825
- Power to overcome it = 363.825 * 30 = 10 914.8
- Same power = 10 914.8 / 745.69987158227022 = 14.6369
- Power at twice the speed = 0.5 * 1.225 * 0.3 * 2.2 * (2*30)^3 = 87 318
- Drag area CdA = 0.3 * 2.2 = 0.66
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
Compare a saved scenario
Recent calculations
The formula
- F = (1/2) rho Cd A v^2
- P = F v = (1/2) rho Cd A v^3
Doubling speed multiplies the drag power by eight. Above about 80 km/h a car spends most of its fuel on air.