Wind Pace Calculator
8:17/mi
+17s/mi
Headwind 10 mph · still air 8:00 /mi · +17s /mi
- Headwind
- 8:17/mi
- Tailwind
- 7:51/mi
- Crosswind
- 8:02/mi
- Out & back
- 8:04/mi
+17s /mi · 5:09 /km
−9s /mi · 4:53 /km
+2s /mi · 5:00 /km
+4s /mi · 5:01 /km
Wind-adjusted
Still air 8:00 /mi · 4:58 /km · 7.50 mph in a 10 mph wind: headwind +17s /mi, tailwind −9s /mi, crosswind +2s /mi, out-and-back net +4s /mi.
Equal-effort estimate from an air-drag model. Wind at runner height varies with shelter and gusts.
Air-drag estimate — not VDOT, not McMillan, not medical advice. Other conditions: heat pace · altitude pace · grade-adjusted pace · pace calculator.
Worked examples
8:00 /mi still air · 10 mph headwind
8:17 /mi · 5:09 /km · +17s /mi · +11s /km
8:00 /mi still air · 10 mph tailwind
7:51 /mi · 4:53 /km · −9s /mi · −5s /km
8:00 /mi · 10 mph out-and-back
Average 8:04 /mi · 5:01 /km · +4s /mi net
8:00 /mi · 10 mph crosswind
8:02 /mi · 5:00 /km · +2s /mi
How it works
An estimate, from a simple air-drag model. Running costs about 3.9 J/kg per metre on the flat; on top of that, air resistance costs in proportion to the square of the air speed past you. In still air that drag share is small — about 1.5% at 8:00/mi and roughly 3–5% at 5–6 m/s, in the few-percent range reported by Pugh (1971) and Davies (1980). A headwind raises the air speed to runner speed plus wind speed, so drag grows fast. The page finds the pace that keeps your metabolic power — your effort — the same as your still-air pace, by bisection.
Forecast wind is measured 10 m up; at chest height over open ground it is roughly two-thirds of that, so the model uses 0.65 × the wind you enter. A tailwind is credited with half of what the same headwind costs, capped at twice the still-air drag — you cannot bank all of a push. A crosswind only adds the drag component along your direction of travel, a small fraction of a headwind. Out-and-back is half each way: the average pace is slower than still air because the headwind leg costs more than the tailwind leg returns.
- cost C(v) = 3.9 + k · u·|u| J/kg/m, u = v + 0.65·wind
- k set so drag = 1.5% of cost at 8:00/mi still air
- tailwind saving = ½ × headwind extra, cap 2 × still drag
- crosswind drag = k · v · √(v² + w²)
- same effort: C(v′, w) · v′ = C(v, 0) · v
- out-and-back pace = (head pace + tail pace) ÷ 2
Wind is input 0–40 mph (0–64 km/h). Gusts, drafting in a pack, and the balance cost of a strong crosswind are not modelled — treat the result as a pacing guide and run by effort. Same even-pace mile as the running pace calculator · heat pace · altitude pace · grade-adjusted pace · treadmill. Not medical or coaching advice.
FAQ
What is a wind pace calculator?
A wind pace calculator estimates the pace that matches your still-air effort in a headwind, tailwind, crosswind, or on an out-and-back course. Default 8:00 per mile in a 10 mph headwind is about 8:17 per mile (+17 seconds). There is no Calculate button; results update live.
How much does a headwind slow you down?
With this model, a 10 mph headwind costs about 17 seconds per mile at 8:00/mi (+11 s/km), a 20 mph headwind about 43 seconds. Faster runners lose a bit less time per mile but a larger share of effort, because drag grows with the square of air speed.
Does a tailwind give back what a headwind takes?
No. A tailwind helps roughly half as much as the same headwind hurts — at 8:00/mi a 10 mph tailwind is worth about 9 seconds per mile. This page credits half the headwind cost and caps the benefit. That is why an out-and-back run in wind averages slower than still air: about +4 s/mi at 10 mph.
What about a crosswind?
A pure crosswind adds only the drag component along your direction of travel, so its effect is small — about +2 s/mi at 10 mph and 8:00/mi, roughly a seventh of the headwind cost. Gusts and the balance cost of strong side wind are not modelled.
Where does the model come from?
Air resistance is a few percent of running energy cost at distance speeds (Pugh 1971; Davies 1980). SplitLab sets drag to 1.5% of cost at 8:00/mi in still air, scales it with the square of air speed, uses 0.65 × forecast wind for runner height, and solves for equal metabolic power by bisection. It is an estimate, not VDOT, not McMillan, and not a lab measurement.