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Cycling power and speed calculator
Your speed at a given power, or the watts a target speed takes, on the flat or a rolling road.
On a climb? Climb time Power-to-weight chart FTP and zones
Speed on the flat by power
| Power | Tops | Drops | Aero bars |
|---|---|---|---|
| 100 W | 25.5 15.8 mph | 26.7 16.6 mph | 27.8 17.2 mph |
| 150 W | 29.7 18.4 mph | 31.1 19.3 mph | 32.4 20.1 mph |
| 200 W | 33.0 20.5 mph | 34.6 21.5 mph | 36.0 22.4 mph |
| 250 W | 35.7 22.2 mph | 37.5 23.3 mph | 39.1 24.3 mph |
| 300 W | 38.1 23.7 mph | 40.0 24.9 mph | 41.7 25.9 mph |
| 350 W | 40.3 25.0 mph | 42.3 26.3 mph | 44.1 27.4 mph |
| 400 W | 42.2 26.2 mph | 44.3 27.6 mph | 46.2 28.7 mph |
km/h, model estimates for a 72 kg rider on an 8.5 kg bike: flat road, calm air, 15 °C at sea level, Crr 0.0032. Each figure opens the calculator with those numbers.
Model estimates, not tested by us. Steady speed from the road cycling power model of Martin et al. (1998), which matched SRM-measured power to a 2.7 W standard error: air drag, rolling resistance, wheel bearings and gravity, over a chain efficiency of 97.6%, with wheel rotation drag 0.0044 m². Wind adds to the air speed the way the paper does it (air speed = ground speed + wind along the road). Position presets are wind-tunnel drag areas: tops 0.358 and drops 0.307 (Jeukendrup & Martin, 2001) and aero bars 0.269 (Martin et al., 1998). Riders vary a lot, so use your own CdA if you know it. Crr 0.0032 is Martin's figure for high-pressure road clinchers on smooth asphalt; the paper says rolling resistance depends on tire pressure, tread, casing and the road surface, and cites values from .0016 (silk track tire) to .0066 (touring tire). Descents assume no braking. Same model as the climb time calculator. Sources: Martin et al. 1998, J Appl Biomech 14:276-291; Defraeye et al. 2010, J Biomech, Table 1 (Jeukendrup & Martin 2001 drag areas; accepted manuscript); NASA Glenn Earth atmosphere model (air density).