Estimate how many calories you burn in a day and how many to eat for your goal. Enter your sex, age, height, weight and activity level; the tool works out your resting metabolism, scales it for activity to a maintenance figure, and offers gentle and standard targets for losing or gaining weight. It’s an educational estimate and runs on your device.
Enter your details to estimate daily calories.
These are educational estimates based on population averages, not personalised medical or nutritional advice. Individual needs vary. Consult a doctor or dietitian before making significant dietary changes.
How it works
Resting burn (BMR) uses the Mifflin–St Jeor equation, the one most dietitians prefer: 10×kg + 6.25×cm − 5×age, plus 5 for men or minus 161 for women. Multiplying BMR by an activity factor (1.2 sedentary up to 1.9 very active) gives your maintenance calories — roughly what keeps your weight steady.
The goal targets adjust maintenance by a fixed energy gap: −250 kcal/day for gentle loss (about 0.25 kg/week), −500 for standard loss (about 0.5 kg/week), and the same amounts added for gaining. These are starting points; real results depend on food accuracy, adherence and how your body adapts.
Practical examples
Sedentary office worker
A 30-year-old man, 80 kg, 180 cm, sedentary: BMR 1,780 kcal, maintenance about 2,136 kcal. To lose ~0.5 kg a week he’d aim for roughly 1,636 kcal.
Active trainer
The same person at the “active” level has a much higher maintenance, which is why activity level matters more than most people expect — guessing it too high is a common reason a plan stalls.
Gaining muscle
A lifter wanting to add weight takes the +250 or +500 target and pairs it with adequate protein and training. The calculator sets the calorie ceiling; the gym decides what the surplus becomes.
Frequently asked questions
What is BMR and how does it differ from maintenance?
BMR (basal metabolic rate) is the energy your body uses at complete rest just to stay alive. Maintenance, often called TDEE, is BMR multiplied by an activity factor to include daily movement and exercise — it’s the figure that keeps your weight stable.
Which equation does it use, and why?
Mifflin–St Jeor, published in 1990 and generally the most accurate of the common formulas for modern populations. It tends to be a little lower than the older Harris–Benedict equation, which overestimates for many people.
How do I choose my activity level?
Sedentary is desk work with little exercise; light is 1–3 workouts a week; moderate 3–5; active 6–7; very active is hard daily training or a physical job. When unsure, pick the lower option — overestimating activity is the most common mistake.
Why does 0.5 kg a week mean about 500 fewer calories a day?
A kilogram of body fat stores roughly 7,700 kcal, so half a kilo is about 3,850 kcal — close to 500 per day over a week. It’s a useful rule of thumb, though the body doesn’t burn fat quite so linearly in practice.
Are these numbers exact?
No. They’re estimates with real person-to-person variation from genetics, muscle mass and non-exercise movement. Use the maintenance figure as a starting point, track your weight for two to three weeks, and adjust based on what actually happens.
Should anyone avoid large calorie cuts?
Yes. Very low intakes can be unsafe and hard to sustain, and needs differ for pregnancy, teenagers, older adults and medical conditions. This tool is general guidance, not a prescription — check with a professional before big changes.
Does it tell me what to eat?
No, only how much energy to aim for. Protein, fibre and food quality matter enormously for how a calorie target feels and works. Pair the number with a sensible, balanced diet rather than chasing calories alone.
Are my details kept private?
Yes. Everything is computed in your browser; nothing is uploaded and analytics never receives your inputs.
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