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Wind-Adjusted Running Pace Calculator

Work out what the wind costs you per kilometre — and what a tailwind gives back.

How it is calculated

The tool keeps your metabolic effort equal to that of your calm-air pace and solves for the speed that costs the same with wind. Effort is P = 3.6 × m × v + Pair / 0.40, with body mass m in kg, ground speed v in m/s, 3.6 J/kg/m as the flat running cost and 0.40 as the efficiency of overcoming air. Air power is 0.5 × 1.225 × 0.24 × vair × valong × v, where the along-track speed is v + wind for a headwind, v − wind for a tailwind and just v for a crosswind, which still adds some air speed. The tool solves for v by bisection. The calm-air reference already includes the air you create by running, so with 0 km/h wind the adjusted pace equals your flat pace. Pace is entered as minutes and seconds in separate boxes (seconds below 60), wind in km/h (0–120), weight in kg (up to 400). In a strong tailwind the air power turns negative, meaning the wind is helping.

Worked example

Calm-air pace 5:00 /km (12.0 km/h), 70 kg, 20 km/h headwind. Wind speed is 20 / 3.6 = 5.56 m/s. The tool finds the ground speed whose total effort equals the calm-air effort, and that speed is 11.0 km/h. Pace then is 60 / 11.0 = 5.45 min, which is 5:27 /km, 27 s per km slower. In that headwind about 83 W of metabolic power goes into air resistance, 9.76% of the total. A 20 km/h tailwind gives 4:53 /km, only 7 s per km faster, and a crosswind 5:04 /km.

Try this example →

Common mistakes

  • Entering the wind speed in m/s or mph. The field is km/h, so 10 mph must be typed as about 16.
  • Choosing 'tail' for a wind blowing from behind you but taking the headwind result for the return leg. Each direction is a separate calculation.
  • Expecting a tailwind to cancel a headwind of the same speed. Air drag grows with the square of speed relative to the air, so the headwind costs 27 s per km while the same tailwind returns only 7 s per km.
  • Using your current windy pace as the flat pace. The input is your calm-air pace at the effort you want to hold.
  • Typing 60 or more in the seconds box, which is rejected. Enter 5 min 0 s for 5:00.

Sources

About this calculator

Wind resistance costs a runner disproportionately more in a headwind than a tailwind gives back at the same wind speed, because aerodynamic drag scales with the square of relative air velocity — running into a wind adds your speed to the wind speed, while running with one subtracts it, so the headwind penalty is always larger in magnitude than the tailwind benefit. This asymmetry means that an out-and-back run in steady wind, or a race with a headwind on one half of the course, will net out slower overall than running the same route with no wind at all.

Runners use a wind-adjustment calculation to set a realistic pace target for windy race days or outdoor tempo sessions, translating a goal 'effort' pace into the actual clock pace they should expect to hold into a headwind, across a crosswind, or aided by a tailwind. It's particularly relevant for coastal and exposed-course races where wind, not just hills, is a major pacing variable.

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