Is Speeding Worth It?
Quick answer: usually not. Driving 75 instead of 65 mph for 30 miles saves about 3 min 42 s, and that assumes no traffic at all. In return you use more fuel, need about 25 m (81 ft) more to stop, and if something blocks the road where you would have stopped at 65, you hit it at about 44 mph. Enter your own trip below.
Updated · formulas checked against the sources below
Fatal crash risk at this speed difference, by the WHO "1% faster → 4% more fatal crash risk" rule (power model, exponent 4): about +77%. That rule describes average speeds across many drivers, so read it as a scale, not a personal forecast. Default shown: 30 miles, 65 mph limit, 75 mph, 30 mpg.
And the fine? Check what this speed would cost you with the UK speeding fine calculator (fixed penalty and court bands A-C), the speeding fines in Europe table for Germany, France, Spain, Italy and the Netherlands, and how long penalty points last. Cameras near you: speed camera map.
How the time saved is worked out
Time falls with 1 ÷ speed, so each extra mph saves less than the one before. Going from 30 to 40 mph saves 30 seconds a mile; going from 70 to 80 mph saves under 7 seconds a mile.
Worked example
A 30-mile motorway or interstate trip with a 65 mph limit, driven at 75 mph the whole way:
If traffic only lets you cruise for 60% of the trip, the saving drops to about 2 minutes 13 seconds, because the slower parts take the same time either way.
Fuel
Air resistance grows with the square of speed, so cars use more fuel per mile at motorway speeds. The US Department of Energy says mileage usually falls quickly above 50 mph and that slowing by 5-10 mph saves 7-14%. The calculator models that as 1.4% more fuel per mile for every mph above 50 mph (80 km/h), compared with the economy you enter for the speed limit. Your car may do better or worse.
Stopping and impact speed
Stopping distance uses a 1.5-second reaction and dry-road braking (μ = 0.8), as on our stopping distance calculator. The "speed left at the hazard" assumes something blocks the road exactly where a driver at the limit would just stop: the faster driver covers more ground before braking and has less room left to brake in.
Minutes saved by speeding (mph)
| Limit → your speed | 5 miles | 20 miles | 100 miles | Extra stopping | Speed left at hazard |
|---|---|---|---|---|---|
| 25 → 35 mph | 3.4 min | 13.7 min | 68.6 min | +47 ft | 34 mph |
| 30 → 40 mph | 2.5 min | 10.0 min | 50.0 min | +51 ft | 35 mph |
| 45 → 55 mph | 1.2 min | 4.8 min | 24.2 min | +64 ft | 39 mph |
| 55 → 65 mph | 0.8 min | 3.4 min | 16.8 min | +72 ft | 42 mph |
| 65 → 75 mph | 0.6 min | 2.5 min | 12.3 min | +81 ft | 44 mph |
| 70 → 80 mph | 0.5 min | 2.1 min | 10.7 min | +85 ft | 45 mph |
| 70 → 90 mph | 1.0 min | 3.8 min | 19.0 min | +178 ft | 65 mph |
Minutes saved by speeding (km/h)
| Limit → your speed | 10 km | 50 km | 200 km | Extra stopping | Speed left at hazard |
|---|---|---|---|---|---|
| 30 → 50 km/h | 8.0 min | 40.0 min | 160.0 min | +16 m | 50 km/h |
| 50 → 60 km/h | 2.0 min | 10.0 min | 40.0 min | +10 m | 44 km/h |
| 50 → 70 km/h | 3.4 min | 17.1 min | 68.6 min | +20 m | 64 km/h |
| 80 → 100 km/h | 1.5 min | 7.5 min | 30.0 min | +26 m | 73 km/h |
| 100 → 120 km/h | 1.0 min | 5.0 min | 20.0 min | +30 m | 78 km/h |
| 120 → 140 km/h | 0.7 min | 3.6 min | 14.3 min | +34 m | 83 km/h |
| 130 → 160 km/h | 0.9 min | 4.3 min | 17.3 min | +55 m | 106 km/h |
"Speed left at hazard": a hazard sits exactly at the stopping point of a driver at the limit (1.5 s reaction, dry road). In town, a pedestrian hit at the speeds in this column faces a much higher risk of death; see crash speed and survival.
Assumptions
- Time saved assumes you hold the higher speed for the share of the trip you enter, with no extra stops. Real trips include junctions, lights and traffic.
- Fuel is a simple straight-line model of the fueleconomy.gov guidance for petrol and diesel cars; electric cars lose range with speed in a similar way, but the price inputs would differ. Results are estimates.
- Stopping distance assumes an alert driver (1.5 s), good tyres and brakes and a dry, level road. Wet roads at least double the braking part.
- The WHO 1%→4% rule is about average speeds across a road network. It shows the scale of the effect; it is not your personal risk.
- Fines depend on the country, state, the road and how far over the limit you were: use the fine calculators linked above.
Is speeding worth it? — FAQ
How much time do you actually save by speeding?
Is going 10 mph over the limit worth it?
Does driving faster use more fuel?
Why does speeding save so little time in town?
How much further does it take to stop when speeding?
Sources and method
- U.S. Department of Energy / EPA, fueleconomy.gov: Driving more efficiently — mileage falls rapidly above 50 mph; slowing 5-10 mph saves 7-14%; each 5 mph over 50 ≈ $0.30 a gallon at $4.28 (US government work)
- World Health Organization: Road traffic injuries fact sheet — every 1% increase in mean speed → 4% increase in fatal crash risk
- Our stopping distance calculator and method — reaction 1.5 s, μ = 0.8 dry
Method: time = distance ÷ speed; fuel factor 1 + 0.014 × (mph − 50) above 50 mph (km/h converted to mph first); stopping = v·1.5 + v²/(2·0.8·9.81); risk ratio = (your speed ÷ limit)^4. The calculator runs in your browser and nothing you type is sent. Checked 2026-11-02.