What this page does
A running calorie calculator answers one question: how much energy does this run cost. This one answers it from three inputs — body mass, the distance you covered, and the gradient of the route — and from nothing else. There is no MET table behind it, no heart-rate estimate and no accelerometer. The cost per metre comes from a published fit of measured oxygen consumption, and the kilocalories are that cost multiplied by your mass and your distance.
The distance can be typed directly, or worked out from a speed and a time: speed times time is the distance, and the distance is what the fit prices. Body mass goes in as kilograms or pounds, distance as kilometres or miles, and the gradient as a percentage from −45% to +45%.
No other page on this site prints kilocalories. The fat burning heart rate page states plainly that it does not estimate calories or grams, because turning an intensity into a rate needs a substrate measurement it does not have; this page takes the other route, pricing the distance instead of the intensity. What it prints is kilocalories only — it says nothing about fat grams or about which fuel the kilocalories came from. The treadmill pace calculator and the treadmill pace conversion turn a belt speed into an outdoor pace; this page turns a distance into kilocalories, and it does not convert pace at all.
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 model and its citation are written up below.
How the number is calculated
One published thing goes in: the metabolic cost of running one metre as a function of gradient, measured on a treadmill across gradients from −45% to +45% and published by Minetti and colleagues in 2002. In their fit the cost of running one metre at gradient i, in joules per kilogram per metre, is:
C(i) = 155.4i5 − 30.4i4 − 43.3i3 + 46.3i2 + 19.5i + 3.6
Minetti A.E., Moia C., Roi G.S., Susta D., Ferretti G. (2002), Journal of Applied Physiology 93(3):1039–1046, DOI 10.1152/japplphysiol.01177.2001. At zero gradient the polynomial returns C(0) = 3.6. The paper reports a level cost of about 3.40 J·kg⁻¹·m⁻¹ instead; this page uses the polynomial as published, exactly as the rest of this site does, so its flat number sits about 6% above the paper's measured flat cost — and that gap is a property of the published fit, not a mistake here.
The second thing that goes in is a definition, not a measurement: 1 kcal = 4184 J, the thermochemical calorie. So the kilocalories for a body of mass m kilograms covering d metres at gradient i are:
E = C(i) × m × d ÷ 4184
Distance is either the number you typed, or speed × time: a run at v km/h for t seconds covers d = v × 1000 ÷ 3600 × t metres. Two unit definitions carry the rest: 1 lb = 0.45359237 kg exactly, and 1 mile = 1609.344 m exactly (the 1959 international yard and pound agreement).
A worked example: 70 kg over 10 km on the flat
With i = 0, m = 70 and d = 10000: E = 3.6 × 70 × 10000 ÷ 4184 = 2,520,000 ÷ 4184 = 602.29 kcal, printed 602 kcal. The same arithmetic per unit of distance gives 60.2 kcal per kilometre and 96.9 kcal per mile, which is what the table above lists for a 70 kg row. On a 5% climb C(0.05) = 4.6852, so the same 10 km costs 4.6852 × 70 × 10000 ÷ 4184 = 783.85 kcal, printed 784 kcal — 1.30 times the flat cost. On a 5% descent C(−0.05) = 2.7459, so the same distance costs 459.40 kcal, printed 459 kcal.
Why the speed is not in the cost
The fit has no speed term. It prices the distance and the climb, not the pace, so a 70 kg runner covering 5 km on the flat spends 301 kcal whether that takes 37:30 at 8 km/h or 21:26 at 14 km/h. That is a property of the published fit, and it is why the speed input on this page feeds the distance rather than the cost: the clock changes, the energy for the same distance does not. What changes the energy is more distance, more body mass, or more climb.
The body-mass table, and how to read it
The table above holds one row for each body mass from 50 to 110 kg on the flat, with the kilocalories for the four measured race distances — 5000 m, 10000 m, 21097.5 m and 42195 m — and the cost of one kilometre next to each. The row nearest the mass you typed is highlighted, so the table reads at a glance rather than being a separate reference you have to hunt through.
Two notes on reading it. Every cell is the same arithmetic as the answer above with the gradient set to 0, so a row can be checked by hand: 70 kg over 5000 m is 3.6 × 70 × 5000 ÷ 4184 = 301.15, printed 301. And the table stops at 110 kg only because a printed table has to stop somewhere — the tool itself takes any mass from 30 to 200 kg.
Gradient, and the treadmill belt
Gradient is rise over run: 5% means 50 m of climb in 1000 m, and it enters as i = 0.05. The second table above lists the fit's cost at twelve gradients, that cost as a multiple of the flat cost, and the kilocalories for your own mass and distance at each. The shape of it is not a straight line: +5% costs 1.30 times the flat cost, +10% costs 1.66 times, but the curve bottoms out near −18% and then turns back up, because a very steep descent costs energy again. At −20% the fit returns exactly 1.8000 J/kg/m, half the flat cost, and at −45% it is back above the flat cost at 4.0323.
A course that goes up and then down is not the same as its net average, because the curve is curved. An out-and-back at ±5% averages (4.6852 + 2.7459) ÷ 2 = 3.7156 J/kg/m, which is 3.2% more than the flat 3.6 — so a run with 5% up and 5% down costs more than the same distance on the flat, even though it starts and finishes at the same elevation. This page prices the one gradient you type over the whole distance; it does not read a profile.
For a treadmill, the console's distance is the belt distance and the incline is the gradient, so the same arithmetic applies directly: C(i) × mass × belt distance ÷ 4184. What this page does not do is turn a belt speed into an outdoor pace — that is the treadmill pace calculator for an incline, and the treadmill pace conversion for the flat belt. A flat belt also removes the wind you would push against outdoors, so a flat-belt session and a flat-road run at the same distance come out identical here; the road run costs a little more, and this page does not print a number for how much, because it has no source for that difference in kilocalories.
Walk, run, and what this fit prices
The polynomial on this page is the paper's running fit. The same paper also reports a walking fit; this page does not carry it, so it refuses a speed below 6.0 km/h rather than extrapolating a running curve down to a walk. Walking is a different gait with a different cost per metre and a different shape of curve, and pricing a walk with a running fit would give a number with no source behind it. If you walked, this page has no answer for you, and it says so instead of printing one.
Within the running range, the other half of the same point: the fit has no speed term, so two runs of the same distance and the same climb come out the same whatever the pace. A 70 kg runner covering 5 km flat at 8 km/h spends the same 301 kcal as the same runner covering it at 14 km/h — 37:30 against 21:26, same energy. If you want a smaller number, the levers this model has are less distance, less body mass, or less climb. Pace is not one of them.
That is also the honest limit of any distance-based calorie model: it knows what moving your mass over that ground costs, and nothing about how hard the effort felt. Two runners of the same mass covering the same 10 km get the same number here even if one of them is far fitter than the other, because the fit prices the work done against gravity and the ground, not the cost to the person doing it.
Supported range and limits
- Body mass: 30 to 200 kg, or 66 to 441 lb. Converted once, at the point of entry, with 1 lb = 0.45359237 kg.
- Distance: 100 m to 100 miles, entered as 0.1 to 160.9 km or 0.062 to 100 miles. In speed mode the distance is speed × time and must land inside the same window.
- Speed: 6.0 to 30.0 km/h, or 3.7 to 18.6 mph. Below 6.0 km/h the page refuses, because that is a walking speed and the fit is a running fit.
- Gradient: −45% to +45%, the range the study measured. Anything outside it is refused, not clamped silently.
- One gradient for the whole run. The page does not read an elevation profile, so a rolling course has to be entered as the one gradient you want priced.
- Rounding: kilocalories to the nearest whole number, cost per km, per mile and per hour to one decimal, the fit's cost to four decimals. 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 fat grams, and no fuel split. It prints kilocalories and nothing about how much of them came from fat or carbohydrate. That needs a substrate measurement per person, which no distance-based fit carries.
- No weight-loss arithmetic and no promise. No deficit, no target intake, no rate of loss, no “how long until I lose X”. The number is the energy one run costs; what you eat around it is outside this page.
- No heart-rate model. Heart rate is not an input and is not estimated from the answer. Two people with the same mass and the same run get the same number here whatever their heart rates did.
- No MET table. MET values are a different convention with their own published compendium; this page does not use one, and does not convert between its number and a MET value.
- No walking cost. The fit on this page is the running fit. Speeds below 6.0 km/h are refused rather than priced with it.
- No weather correction. Heat, headwind and humidity change the cost of a run. This page prices none of them, and adding an unsourced adjustment would make the number look more precise than it is.
- No medical or dietary advice. A kilocalorie is arithmetic, not a health assessment. If you have a condition that affects exercise or eating, the number here is not a target.
- No training plan. No sessions, no durations, no intervals, no weekly volume, no programme.
- No belt-speed to outdoor-pace conversion. That is the treadmill pace calculator and the treadmill pace conversion; this page prices the belt distance, it does not translate the belt.
Questions
How many calories do you burn running 5 km?
It depends on body mass, because the fit is per kilogram. On the flat a 60 kg runner spends 258 kcal over 5 km, a 70 kg runner 301 kcal, and an 80 kg runner 344 kcal — the table above lists every 5 kg from 50 to 110. The arithmetic for 70 kg is 3.6 × 70 × 5000 ÷ 4184 = 301.15, printed 301. A climb adds to it: at +5% the same 5 km costs 392 kcal for a 70 kg runner.
How many calories does running burn per kilometre?
On the flat, 3.6 × body mass ÷ 4184 kilocalories per kilometre, which is 60.2 kcal for a 70 kg runner and 68.8 kcal for an 80 kg runner. Per mile it is 1609.344 ÷ 1000 times that: 96.9 kcal for 70 kg. The cost per kilometre does not depend on how fast you ran it, because the published fit has no speed term — only the mass and the gradient move it.
Does running faster burn more calories?
Not for the same distance, in this model. The fit prices the distance and the climb, so 5 km on the flat is 301 kcal for a 70 kg runner whether it takes 37:30 at 8 km/h or 21:26 at 14 km/h. Running faster does burn more per hour, because you cover more ground in the hour: at 14 km/h the same runner is at 843 kcal per hour against 602 kcal per hour at 10 km/h.
How many calories does running burn compared with walking?
This page cannot answer that, and does not guess. The polynomial it uses is the running fit from the 2002 paper; the same paper reports a separate walking fit, which this page does not carry. Walking has a different cost per metre and a differently shaped curve, so the page refuses any speed below 6.0 km/h instead of running the numbers for a walk through a running model. A walking number printed here would have no source behind it.
How much does an incline change the calories?
By the ratio of the fit's cost at that gradient to its cost on the flat. For a 70 kg runner over 10 km: flat is 602 kcal, +2% is 671 kcal (1.11 times), +5% is 784 kcal (1.30 times), +10% is 999 kcal (1.66 times), and −5% is 459 kcal (0.76 times). The curve is not a straight line and it is not symmetric: it bottoms out near −18% and climbs again on steeper descents, so a very steep downhill costs more than a gentle one.
Does a treadmill calorie count match running outdoors?
The distance on the console is the belt distance and the incline is the gradient, so the same arithmetic applies and a flat-belt run and a flat-road run of the same distance come out identical on this page. Outdoors the same distance costs a little more, because the belt removes the wind you would be pushing against. This page does not print that difference, because it has no source for it in kilocalories — the site's 1% convention (Jones and Doust, 1996) is a pace convention, and applying it to energy would be an invention.
Why is this number different from my watch?
Because the inputs are different. A watch estimates from heart rate and from arm movement, and it updates as those change during the run. This page prices distance, body mass and gradient with one published fit and does not look at your heart rate at all. Neither number is a measurement of your metabolism; they are two different models, and this page only claims the one it can cite.
Does this page tell me how much to eat or how much weight I will lose?
No. It prints the kilocalories one run costs and stops there. There is no deficit arithmetic, no target intake, no rate of weight change and no dietary or medical advice anywhere on the page — those need things this calculator does not know, and inventing them would be worse than leaving them out.