Calories burned walking
What a walk actually costs — net of the resting energy you would have spent anyway, which is the number your watch reports and almost no calculator shows.
180kcal
matches active energy
- Gross, including resting
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- Resting over the same time
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- Distance
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- Net per km
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- MET used
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- Share of a 500 kcal deficit
Estimates from speed carry roughly ±15–20%, wider on a gradient. Do not eat these back: treating an estimated burn as earned food is the most reliable way to walk a great deal and lose nothing.
Net and gross — why your watch shows less
Nearly every calculator for this reports gross calories: the total your body spent during the walk, including the energy it would have spent anyway sitting on the sofa. Apple Health's active energy is net — total minus an estimate of your resting rate. The gap is 15–25% of the figure, which is why the number on a website so rarely matches the number on your wrist, and why people conclude one of the two is broken.
Neither is broken; they are answering different questions. If you are adding the walk on top of a maintenance figure that already includes your resting burn, net is the honest number — counting the resting part twice would be double-counting. That is why net is the headline here.
This page takes the resting rate from Mifflin–St Jeor rather than the 1 MET convention, because 3.5 mL of oxygen per kilogram per minute overstates resting metabolism for most adults, and especially for women, older and heavier people.How accurate is Apple Watch calorie tracking goes into what the watch does with all this.
How the figure is worked out
On the flat, from MET values in the 2011 Compendium of Physical Activities, interpolated between the published speed bands rather than stepped — so 5.1 km/h and 5.2 km/h give sensibly different answers instead of jumping. One MET is 3.5 mL of oxygen per kilogram per minute, and a litre of oxygen is roughly 5 kcal, which gives the familiar MET × 3.5 × kg ÷ 200 per minute.
The edition matters more than you would think. The 2024 revision of the Compendium raises several walking values — brisk walking goes from 4.3 to 4.8 METs — so two calculators can disagree by 10% purely by citing different years. This page uses 2011 throughout and says so.
Incline changes everything
Set a gradient above zero and the page switches to the ACSM walking equation, which models the vertical component explicitly. Walking uphill is the cheapest way to make a walk cost more without walking faster or longer: a 5% incline adds roughly half again to the energy cost at the same speed. Downhill, the equation does not model the saving well, so descents are treated as flat.
What a walk is worth, and what it is not
A brisk 45-minute walk comes to a couple of hundred net calories for most people. Against a 500 kcal daily deficit that is a meaningful share — but it is also one pastry, which is the uncomfortable arithmetic at the centre of this whole subject. Walking is excellent for a great many things, including making a deficit easier to hold. It is a slow way to create one on its own.
To see what that means for a goal, thedeficit calculator puts the burn and the intake side by side.
How accurate is this?
The MET route assumes you walk with average efficiency, which most people roughly do — walking is a well-practised movement. The larger errors come from the inputs: speed guessed rather than measured, and incline ignored on a route that was not flat. Treat it as a figure with a band of about a fifth either side, and use the trend across weeks rather than the number for any single walk.
General information, not medical advice. If you have been sedentary, are pregnant, or are managing a cardiac or joint condition, talk to a clinician before adding much.