Flat pace doesn't tell the whole story on fell, trail and mountain terrain. Use our free calculator to convert hill pace to a flat-equivalent effort, or estimate your finish time on a hilly race.
Enter a pace and a gradient to see the flat-equivalent effort — or work the other way, from a flat pace to what that effort should feel like on a hill.
Enter your race distance, total ascent, total descent and a flat-equivalent goal pace (e.g. your recent 10K or half marathon pace) to get a ballpark estimate of your finish time on a hilly course.
Best suited to races up to marathon distance, where a steady effort is realistic. For ultramarathons, fatigue, fuelling and walk breaks matter more than gradient alone — see the note below.
This is a simplified estimate based on a characteristic gradient derived from your total ascent and descent — it doesn't account for technical or runnable underfoot terrain, altitude or pacing strategy. On technical fell descents in particular, footing and safety usually limit your speed well before your legs or lungs do, so this model can overestimate the "free speed" a steep, technical descent gives you. For race-specific pacing advice, get in touch.
A formula like the one above is a useful starting point, but it can't know how you personally hold up over 50, 75 or 100km. For real ultra pacing, at Townshend Performance we use each athlete's own training run pacing — how they actually climb, descend and hold form hour after hour in training on similar terrain — to build a race-day pacing plan around them specifically, rather than a generic model.
That means factoring in things a calculator never sees: how much your climbing speed really drops late in a long run, how your legs handle repeated technical descents when tired, and how much time to realistically bank for aid stations and fuelling. It's the difference between a rough estimate and a pacing strategy you can actually race to.
Running uphill costs significantly more energy per metre than running on the flat, while gentle downhills can cost less — up to a point, after which steep descents become costly again due to braking forces. Our calculator uses a running energy-cost model based on research by exercise physiologist Alberto Minetti, the same approach used by GPS platforms like Strava to calculate Grade Adjusted Pace (GAP).
The table below shows roughly how much slower (or faster) your pace will read on different gradients, for the same physiological effort as running 5:00/km on the flat.
| Gradient | Equivalent Pace | vs Flat 5:00/km |
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A calculator gets you a ballpark. A coach who has raced and won on this terrain gets you a race-day pacing strategy built around the actual course. Get in touch or explore our bespoke training plans.