Cardio
Treadmill Pace Converter
Convert treadmill speed to running pace with incline-adjusted flat equivalent, projected race times, and calorie estimates.
Result
The flat-road pace that costs the same effort as 10 km/h at 1%.
863 kcal an hour (running equation)
Race times at this belt speed
If you held this speed for the whole distance.
How to use it
- Enter your treadmill speed and incline. Most treadmills display speed in mph (US) or km/h (Europe) — set the Units toggle to match your display.
- Read the outdoor-equivalent pace: the flat-road pace that costs the same oxygen as your belt speed and incline. A 10 km/h run at 6% incline equals roughly 12.3 km/h on a flat road (4:54/km instead of 6:00/km).
- A 1% incline offsets the missing air resistance on a treadmill (Jones & Doust 1996), so at 1% the outdoor-equivalent pace equals the belt pace. Set at least 1% to better simulate outdoor effort.
- Size the session by time or by distance to see the other one and the calories burned. The calorie figure comes from the ACSM walking or running equation and is an estimate: stride efficiency, fitness and heat move it.
- Projected race times at the bottom assume you sustain current treadmill speed for the full distance. These are theoretical — real race times include fatigue, fueling, and terrain variation.
Questions people usually ask
Why does incline affect equivalent flat pace?
Running uphill requires significantly more oxygen per minute at the same speed. In the ACSM running equation each 1% of grade adds 4.5% to the speed-dependent oxygen cost (about 4% of the total at 10 km/h). At 6% incline and 10 km/h you are working about as hard as 12.7 km/h on a flat belt, or about 12.3 km/h on a flat road.
What is the standard incline for outdoor equivalence?
1%. Jones and Doust (1996) found a 1% treadmill grade matched the energy cost of flat outdoor running at 10.5 to 18 km/h, because a treadmill has no air resistance. Most recreational runners set 1–2% for general training.
How accurate is the calorie estimate?
It comes from the ACSM walking (below 6.5 km/h) or running equation, which predicts average oxygen cost; your own stride efficiency, fitness, heat and fatigue move the real number. Treat it as a planning estimate, not a measurement.
Can I convert treadmill speed to outdoor race pace?
Yes — use the outdoor-equivalent pace. At 1% incline it equals the belt pace; at 0% the road equivalent is about 4.5% slower, because a flat belt is easier than a flat road; above 1% it is faster than the belt pace.
Is this tool free?
Yes. All calculations are client-side. No data leaves your browser.
The formula, worked through
- Formula Treadmill to Outdoor Pace Conversion Formula
Treadmill grade adjustment: 0% treadmill = outdoor pace + 12 sec/km (no wind resistance). +1% grade adds ~3.3% energy cost (Jones & Doust 1996). 1-2% grade simulates outdoor effort.
- Formula Running Pace Formula: Riegel & VDOT Race Pace Conversion
Running pace formula: pace = time / distance, plus Riegel T2 = T1 x (D2/D1)^1.06 for race-equivalent paces. Worked 10K-to-half-marathon example.
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Articles
- 8 min read How to Train for a 5k
A ten-week plan built around polarised training, aerobic base work, and a weekly VO2 max session — with pacing pulled from Riegel.
- 12 min read Marathon Pace and Elevation Adjustments
Marathon pace and elevation: a validated correction for total climb / descent — Strava grade-adjusted pace, Naismith's rule, where they break.
- 8 min read The Minetti Curve: Why Downhill Running Is Cheap Then Brutal
How Minetti's 2002 J Appl Physiol paper defines energy cost across grades, where the eccentric load tax dominates, and the practical pacing rule.
By goal
Use it from code
The same calculation as a JavaScript module you can import. It runs where you import it, with no request, key or rate limit.
import { compute } from "https://aifithub.io/engines/treadmill-pace-converter.js";Input and output contract, TypeScript types and the guide for agents.