i
Log the food in a couple of taps.
Scan a UK barcode, search, or photograph the plate. Calories and macros fill in.
kcalThe UK calories burned calculator
Calories burned calculator. What a workout actually costs.
Pick the activity, your weight and how long you went for. We work out the calories using MET values, the standard measure of how hard an activity works your body.
Activity
MET values from the Compendium of Physical Activities. Between two intensities? Pick the lower one.
Weight
A heavier body does more work to move, so it burns more for the same activity.
Duration (minutes)
01The other side
Burning is easy
to out-eat.
A 30 minute run burns about 400 calories. A muffin and a latte put most of it back. The number that decides your week is the gap between what you burn and what you eat, and the eating side is the one that hides. NutraSafe logs both.
ii
Log the workout out.
Record the session so the day shows the net, not just what went in.
iii
Watch the weekly trend.
A single day is noise. The weekly line tells you whether the gap is doing its job.
iv
Cover the micros too.
14 vitamins and 13 minerals against the UK NRV, so a hard training week still adds up.
02How it's worked out
The maths
behind the burn.
No magic. One formula, three inputs, and an honest margin of error.
Start with the MET
A MET is how hard an activity works you compared with sitting still. Sitting is 1. A brisk walk is about 4.3. Running at 10 km per hour is about 9.8.
1 MET = sitting stillMultiply by your weight
A heavier body does more work to move, so weight scales the burn. This is why the same run burns different amounts for different people.
kcal = MET × kg × hoursAnd the time
Calories add up with minutes. Thirty minutes of the same activity burns half of what an hour does.
Read it as a range
MET values are averages, so your real number depends on intensity and fitness. Use it to compare activities and track effort, not as an exact count.
03Frequently asked
Questions
people ask.
Answers sourced to the Compendium of Physical Activities and the NHS.
How are calories burned during exercise calculated?
From the MET value of the activity, your body weight and how long you do it. Calories burned equals MET times weight in kilograms times time in hours. A MET is the metabolic cost of an activity compared with sitting still, so running at 10 km per hour is about 9.8 METs. The MET values come from the Compendium of Physical Activities.
How accurate is a calories burned calculator?
It is an estimate. MET values are population averages, so your real burn shifts with fitness, intensity, terrain and how efficiently you move. Treat the figure as a ballpark, within roughly 15 to 20 per cent, not an exact count. Fitness watches add heart rate but are not exact either.
Does body weight change how many calories you burn?
Yes. A heavier body does more work to move, so it burns more for the same activity and time. That is why the calculation multiplies by your weight. Two people doing the same 30 minute run can burn noticeably different amounts.
What burns more calories, cardio or weights?
Minute for minute, steady cardio like running or cycling usually burns more during the session than a weights set, because you are moving continuously. Weights build muscle, which raises your resting burn over time. For the calories spent in the session itself, cardio is normally higher.
Should I eat back the calories I burn exercising?
Most people eat back some, not all, because the burn is an estimate and it is easy to undo a deficit. A common approach is to log the workout, eat back around half, and adjust after a couple of weeks of weight data. NutraSafe tracks both the food in and the workout out so you can see the net.
Aaron Keen is the founder of NutraSafe. He built this calculator on the MET values from the Compendium of Physical Activities and checks the figures against the sources himself. About the research →
→More tools
The rest of the
calculators.
Free, no sign-up, sourced to the same UK guidance. Built and checked by the NutraSafe team.
You know the burn.
Now watch the gap.
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