What this page does
A treadmill pace conversion answers the one question a flat-belt session leaves unanswered: what does the speed on the console mean once you are back on the road. The console gives you a belt speed in km/h or mph; on a flat belt, with the missing wind put back as grade per the 1996 measurement Jones and Doust published, that number is the outdoor pace the session is worth — per kilometre, per mile, with finish times for 5K, 10K, half and full and a printable 5K band.
No other page on this site is the flat-belt conversion. The treadmill pace calculator takes a belt speed and an incline and prices the climb or descent into the answer, so it returns the outdoor pace that costs the same effort, not the flat-belt equivalent. The race pace calculator takes two of pace, time and distance for a race you are planning. The 5K pace calculator fixes the distance at 5 km and prints the 5K pace chart from 15:00 to 45:00. This page is the case the rest omit, which is the flat belt, and is the one that answers “I am running on a treadmill at 6.0 mph — what does that get me on race day?”.
Everything runs in your browser. Nothing you type is sent to a server, there is no account and no upload, and the numbers never leave the page. The arithmetic is unit conversion and a fixed 1% convention, both written up below with the citations behind them.
How the numbers are calculated
Two things go in. The first is unit conversion, which is a definition: 1 km = 1000 m exactly; 1 mile = 1609.344 m exactly (the international mile, fixed by the 1959 yard and pound agreement); 1 km/h = 1/3.6 m/s; 1 mph = 1609.344 ÷ 3600 = 0.44704 m/s. From those the seconds per kilometre at a given belt speed v in km/h is:
pkm(v) = 3600 ÷ v pmi(v) = 3600 ÷ (v ÷ 1.609344)
The finish time for a measured race distance D metres is T = D ÷ v, with v in m/s. The four distances this page prints use the measured race lengths: 5000 m for 5K, 10000 m for 10K, 21097.5 m for the half marathon, 42195 m for the marathon. Those are not rounding choices: they are the official distances the IAAF (now World Athletics) ratifies, and the same numbers the rest of this site uses.
The second thing that goes in is the 1% convention. A flat belt removes the wind resistance you would be fighting outdoors, so a flat-belt session at speed v on the console costs less than a flat-road run at v. Jones M. and Doust J.H. (1996), Journal of Sports Sciences 14:321–327, DOI 10.1080/026404196367796, measured runners indoors and out and reported that a 1% treadmill grade most accurately reflects the energetic cost of outdoor running on the flat, at speeds above roughly 8 km/h. The convention this site follows is the same one: a flat belt and a flat road are the same effort at the same speed once the missing wind is priced in, which is the 1% number the measurement quotes. This page implements the flat-belt conversion at that convention. If your belt is set to anything other than 0% you want the treadmill pace calculator, which prices whatever grade you typed.
The conversion itself
Let v be the belt speed in km/h, exactly as the console labels it. Let f be the equivalence factor between flat-belt and flat-road effort at the same speed. The 1% convention says f = 1 by construction for a flat belt (a flat belt at the same speed is the same effort as a flat road once the missing wind is priced in), so the outdoor-equivalent speed is vout = v × f = v. The pace is just the reciprocal in seconds per unit:
pkm = 3600 ÷ vout pmi = 3600 ÷ (vout ÷ 1.609344)
and the finish time for any measured race distance D is T = D ÷ (vout ÷ 3.6) = D × 3.6 ÷ vout:
T5K = 18000 ÷ vout T10K = 36000 ÷ vout
Thalf = 75951 ÷ vout Tfull = 151902 ÷ vout
All four are unit arithmetic on the same vout. The reverse direction is the same arithmetic written the other way: a target finish time T for a measured distance D requires a flat-belt speed of v = D × 3.6 ÷ T km/h, or that divided by 1.609344 in mph. That is what the four-target-time block on the page prints.
- v — the belt speed, in km/h or mph, exactly as the console labels it. 1.0 to 30.0.
- vout — the outdoor-equivalent speed, in the same unit you typed. f = 1 at 0% grade by construction.
- pkm, pmi — the outdoor pace, in seconds per kilometre and per mile.
- T5K, T10K, Thalf, Tfull — finish times for the four measured race distances. 5000 m, 10000 m, 21097.5 m, 42195 m.
- 1 mile = 1609.344 m exactly, fixed by the 1959 international yard and pound agreement — a definition, not a measurement.
A worked example: a belt at 10.0 km/h, flat
With the belt at 10.0 km/h and no incline, vout = 10.0 km/h. The pace per kilometre is 3600 ÷ 10.0 = 360 s, printed 6:00. The pace per mile is 3600 ÷ (10.0 ÷ 1.609344) = 579.36384 s, printed 9:39. The 5K finish is 18000 ÷ 10.0 = 1800 s, printed 30:00. The 10K finish is 36000 ÷ 10.0 = 3600 s, printed 1:00:00. The half is 75951 ÷ 10.0 = 7595.1 s, printed 2:06:19. The full is 151902 ÷ 10.0 = 15190.2 s, printed 4:12:37. The answer is the belt speed, unchanged — which is the check that the flat-belt implementation is wired the right way round.
The reverse: a target 5K of 30:00 needs the belt at 18000 ÷ 1800 = 10.0 km/h, which is 10.0 ÷ 1.609344 = 6.21 mph. A target 5K of 25:00 needs 18000 ÷ 1500 = 12.0 km/h, or 7.46 mph. A target 5K of 20:00 needs 18000 ÷ 1200 = 15.0 km/h, or 9.32 mph. The reverse block on the page prints the same numbers from whichever target you type.
The common-speed table, and how to read a console against it
The table above holds one row for each common belt speed from 3.0 to 12.0 mph, with the km/h, the pace per km and per mile, and the finish times for 5K, 10K, half and full next to each other so the answer for the speed you happen to be running is one glance away. The row nearest your belt speed is highlighted, so the table doubles as a way of reading the page at a glance rather than a separate reference you have to hunt through.
Two notes on reading it. The unit conversion is exact, so a 6.0 mph row will always read 9.66 km/h and 6:13 per km — there is no rounding to second-guess. And the convention this page uses for the flat-belt case is the same one the rest of the site uses: a flat belt and a flat road cost the same effort at the same speed once the missing wind is priced in as the 1% grade the measurement quotes. If you want the version that prices whatever incline you set, the treadmill pace calculator is the right page.
The reverse direction: a target race time to belt speed
Some visitors come to this page with a target race time in mind, not a belt speed. The four-target-time block on the page handles that case: type a target 5K, 10K, half or full time as hh:mm:ss and the page returns the flat-belt speed that delivers it, in km/h and in mph. The arithmetic is the same arithmetic run backwards: a target time T for a measured distance D requires v = D × 3.6 ÷ T km/h. A target 5K of 30:00 needs 18000 ÷ 1800 = 10.0 km/h; a target marathon of 4:00:00 needs 151902 ÷ 14400 = 10.55 km/h.
The reverse direction assumes the same 1% convention as the forward direction. If the belt is set flat and you actually run a flat road course at the printed speed, the finish time on the road matches the target. If the belt is set to anything above 0% the answer on this page overstates the road pace by the cost of that extra grade, applied twice — once in the belt effort, once in the 1% convention. Use the treadmill pace calculator instead, with the incline you actually set.
The 5K pace band you can take to the gym
The band is the same five rows the page already prints, drawn onto a strip of paper 170 mm across. Each row is the outdoor-equivalent clock at the kilometre marker — 1 km, 2 km, 3 km, 4 km and the 5 km finish — so the time on the strip is the clock you would read at each marker if you ran the same effort on a measured 5K course. There is a 50 mm scale check near the top: print the band, hold a ruler against that line, and if it measures 50 mm the band came out the size it was drawn — print dialogs default to “fit to page”, which quietly rescales it.
Every printed time is rounded to the nearest second, so no row is more than half a second from the exact clock. Cut along the border, fold down the middle, and tape the ends around your wrist or rest it on the console. If you have no printer, Download band writes the same rows to a plain-text file and Copy band puts them on your clipboard.
Supported range and limits
- Belt speed: 1.0 to 30.0 km/h, or 1.0 to 30.0 mph — the unit is whichever the console labels. 30.0 km/h is 18.64 mph and 30.0 mph is 48.28 km/h, so the same numeric range means different speeds depending on the unit. Read the label before you read the answer.
- Incline: 0%. This page is the flat-belt conversion. For any incline other than 0% the answer is wrong, and the treadmill pace calculator is the page that prices the incline you set.
- Distances: 5K = 5000 m, 10K = 10000 m, half = 21097.5 m, full = 42195 m. The numbers are the official measured race lengths and are exact definitions, not rounding choices.
- Rounding: times to the nearest second, speed to two decimals, paces to the nearest second. One rounding, at the end, never halfway through a chain.
- Cost: none. No account, no email, no paywall, no daily limit, no request to a server.
- Privacy: every number is computed in your browser. Nothing you type is sent anywhere or stored — reload the page and it is gone.
- Works offline once the page has loaded, and on a phone.
What this page deliberately does not do
- No incline correction. The page takes the belt speed at face value, with the belt flat. A belt set to anything above 0% will produce an answer that is wrong by the cost of that grade, applied twice (once in the belt effort, once in the 1% convention). The treadmill pace calculator is the page that prices the incline you set; the FAQ says how to use both together.
- No calibration correction. The page takes the belt speed at face value. A machine whose real surface speed differs from its console readout will give an answer wrong by exactly that difference, and no arithmetic here can know it. The treadmill pace calculator says how to measure the belt once instead.
- No wind or weather correction. Heat, headwind and humidity all change the road cost of a given speed. This page prices none of them.
- No heart-rate or effort model. The conversion is about the cost of moving a body over a surface, not about how hard it feels on the day. Fitness, sleep and hydration all move the second thing and none of them move the first.
- No prediction from a previous race. This page converts a belt speed into a pace. Turning a recent race into a target finish time is the race time predictor on the home page.
- No fixed-distance extras. No 400 m lap table, no mile-only tables: those live on the 5K pace calculator, the track split calculator and the mile splits calculator.
Questions
How do I convert treadmill speed to outdoor pace?
On a flat belt the conversion is unit arithmetic and nothing more. Divide 3600 by the belt speed in km/h to get seconds per kilometre, or 3600 by the speed in mph to get seconds per mile. A belt at 10.0 km/h on the flat is exactly 6:00 per kilometre and 9:39 per mile outdoors; a belt at 6.0 mph is exactly 10:00 per mile. This page does that conversion for the flat belt only. The version that prices the incline is the treadmill pace calculator.
Is running on a treadmill faster than running outdoors?
On a flat belt, slightly easier — the belt removes the wind resistance you would be fighting on the road, so a flat-belt session at the same speed costs less than the road run at that speed. That is the convention Jones and Doust (1996) measured, and the reason outdoor pace and treadmill pace are not the same number even when the console and the GPS both read the same value. This page returns the outdoor pace the flat belt is worth with that fact already priced in. For a precise incline-aware conversion the page to use is the treadmill pace calculator.
How fast is 6.0 mph on a treadmill in pace per km?
6.0 mph on the flat belt is 6:13 per kilometre and 10:00 per mile outdoors. The pace is the distance divided by the speed: 1000 m divided by 6.0 mph expressed in m/s, which is 6.0 × 0.44704 = 2.6822 m/s, so the time for one kilometre is 1000 ÷ 2.6822 = 372.83 s, printed 6:13. The table on this page holds the same calculation for 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 and 12.0 mph so the answer is one click away without typing anything.
How do I find my 5K pace from a treadmill speed?
Type the belt speed the console shows in the box at the top, and the page returns your 5K pace in the same stats row as the pace per mile and the pace per km. The 5K finish time it prints is the time the same belt would take on the road at the same effort, not on the belt — so a flat-belt session at 6.0 mph prints 30:00 for 5K, which is the time that belt would deliver on a measured 5K course at the same heart rate. Use the print band to take the km-by-km splits to the gym.
What is a good treadmill pace for 5K?
By the road: a 5K in 30:00 needs a 6:00 per km pace, which is 10.0 km/h on the flat belt or 6.2 mph. A 5K in 25:00 needs 5:00 per km, which is 12.0 km/h or 7.5 mph. A 5K in 20:00 needs 4:00 per km, which is 15.0 km/h or 9.3 mph. The pace per km and the 5K finish time move together by definition, so the table on this page lists nine common belt speeds from 3.0 to 12.0 mph with the 5K, 10K, half and full times next to each.
Does treadmill distance match outdoor distance?
On a calibrated flat belt the distance is the same as the distance the console reports, but the effort is not — the belt removes the wind you would push out of the way on the road. This page does the time conversion, not a distance correction. The conversion is also the flat one: it does not apply a 1% incline correction, because the flat belt and the flat road do cost the same energy once the missing wind is put back as grade (Jones and Doust, 1996), and that is the convention this site uses for outdoor pace on the flat. If your belt is set above 0% use the treadmill pace calculator instead.
What is the formula for converting mph to min/km?
Two unit definitions carry the whole calculation: 1 mile is 1609.344 m exactly (1959 international yard and pound agreement) and 1 mph is 1 mile per hour, so 1 mph is 1609.344 ÷ 3600 = 0.44704 m/s. A kilometre at 1 mph therefore takes 1000 ÷ 0.44704 = 2236.94 s, and at any other speed m the seconds-per-km is 2236.94 ÷ m. That is the same as 3600 ÷ (m × 1.609344), and the answer comes back as minutes and seconds: 6.0 mph is 2236.94 ÷ 6 = 372.82 s, or 6:13 per km. The conversion is unit arithmetic, not a model.
Should I set the treadmill incline to match outdoor running?
If you are pricing outdoor pace and the belt is set flat, this page is the right one. If you set the belt to 1% you are already adding back the wind the flat belt removes, and the outdoor pace printed by this page would overstate your road pace by about 1% — the cost of the extra grade, applied twice. The treadmill pace calculator prices whichever incline you set, and the answer it returns is the outdoor pace that costs the same effort, including the 1% convention if you typed it. The two pages are not redundant: this page is the fast flat-belt conversion, the other is the belt-with-incline version with the same Minetti cost model behind both.