Calorie Calculator (TDEE, BMR & Macros)
Your body burns calories all day, even lying still. This calculator estimates how many: first your basal metabolic rate (BMR, the energy for breathing, circulation and keeping organs running), then your total daily energy expenditure (TDEE), which scales BMR by how active you are. From there it sets a daily calorie target for losing, maintaining or gaining weight and splits that target into protein, carbohydrate and fat in grams. Everything works in pounds and feet or kilograms and centimetres, and you can compare the two common BMR equations side by side. It is an estimate for planning, not a prescription.
How to use the calorie calculator (tdee, bmr & macros)
- Pick metric or imperial units, then enter your sex, age, weight and height. In imperial, enter feet in the height box and any extra inches in the inches box.
- Choose the activity level that matches a typical week, not your best week. Most people overrate their activity, so when in doubt choose the lower option.
- Choose a goal. A 500 kcal daily deficit or surplus is the usual starting point; smaller steps are easier to sustain.
- Read the daily calorie target, then use the macro grams as a starting point and adjust after two to three weeks based on how your weight actually trends.
Formula
Mifflin–St Jeor BMR: men = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5; women = 10 × weight + 6.25 × height − 5 × age − 161.
Revised Harris–Benedict BMR: men = 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age; women = 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age.
TDEE = BMR × activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active). Target = TDEE ± your daily adjustment. Roughly 7,700 kcal is one kilogram (about 3,500 kcal a pound) of body weight. Protein and carbohydrate give 4 kcal per gram and fat gives 9 kcal per gram. The calculator will not set a target below 1,200 kcal (women) or 1,500 kcal (men).
Worked examples
A moderately active 30-year-old man
A 30-year-old man weighing 80 kg at 180 cm has a Mifflin–St Jeor BMR of 1,780 kcal. Training three to five days a week (factor 1.55) gives maintenance calories (TDEE) of 2,759 kcal. Choosing “lose weight (−500)” sets a target of 2,259 kcal.
A woman using imperial units
A 35-year-old woman weighing 150 lb at 5 ft 5 in, lightly active, has a BMR of 1,376 kcal and a TDEE of 1,892 kcal. A gentle −250 kcal goal gives 1,642 kcal and an expected change of −0.50 lb a week.
The safety floor in action
A smaller, sedentary 40-year-old woman (50 kg, 155 cm) who selects the −750 kcal option would be pushed below a sensible intake, so the calculator holds the target at 1,200 kcal and flags it. Eating less than that should only be done under medical supervision.
Understanding your numbers
BMR, TDEE and why the activity multiplier matters
BMR typically accounts for around 60–70% of the energy the average person uses in a day. The rest comes from moving (exercise and everyday activity) and from digesting food. The activity multiplier is the biggest source of error in any calorie calculator, because it asks you to summarise a week of life in one choice. If your weight doesn’t change as predicted over two to three weeks, adjust your intake by 100–150 kcal and watch the trend again.
Calorie targets by activity level
| Activity level | Factor | Example TDEE (80 kg, 180 cm, 30 y man) |
|---|---|---|
| Sedentary | 1.2 | 2,136 kcal |
| Lightly active | 1.375 | 2,448 kcal |
| Moderately active | 1.55 | 2,759 kcal |
| Very active | 1.725 | 3,071 kcal |
| Extra active | 1.9 | 3,382 kcal |
Healthy pace of change
Most health organisations suggest gradual weight loss of about 0.5–1 kg (1–2 lb) a week at most. Very large deficits are hard to sustain and can cost muscle, so the calculator’s biggest deficit option is clamped by a safety floor. Gaining weight works the same way in reverse: a modest surplus plus strength training is how people add muscle rather than only fat.
Protein, carbohydrate and fat
The macro splits above are starting points. Higher-protein plans help some people stay full when eating fewer calories; lower-carbohydrate plans suit others. None is magic — the calorie total drives weight change, and the best split is the one you can follow consistently. Use the BMI calculator alongside this one for a fuller picture, and see our guide how to calculate TDEE and daily calories.
Practice problems
Try these yourself first, then check your answer. The answers come from the calculator above.
- A 28-year-old woman, 62 kg, 168 cm, lightly active, wants to maintain her weight. What are her BMR and TDEE?
Show answer
Daily calorie target: 1,882 kcal · Maintenance calories (TDEE): 1,882 kcal
- A 40-year-old man, 200 lb, 6 ft 0 in, moderately active, wants to lose weight at −500 kcal a day. What is his calorie target?
Show answer
Daily calorie target: 2,376 kcal · Maintenance calories (TDEE): 2,876 kcal
Common mistakes to avoid
- Overstating activity. “Moderately active” means three to five hard sessions a week, not a walk to the car and a gym membership. Overestimating it inflates your target by hundreds of calories.
- Treating the number as exact. These equations predict the average person; real individuals can differ by 10% or more, so judge the target by your weight trend over two to three weeks and adjust.
- Cutting too aggressively. A bigger deficit does not mean faster, safer progress — it often costs muscle, energy and consistency.
- Using this during pregnancy, while breastfeeding, for under-18s, or with a medical condition. Needs differ; ask a clinician or registered dietitian.
- Mixing units — typing pounds while metric is selected. Check the unit drop-down first.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body needs at complete rest. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor, so it includes the calories you burn moving, exercising and digesting food. TDEE is the number to compare with what you eat.
Which BMR formula is more accurate, Mifflin–St Jeor or Harris–Benedict?
Studies have generally found Mifflin–St Jeor (1990) closer to measured resting energy expenditure for most adults than the original 1919 Harris–Benedict equation. This tool offers the revised Harris–Benedict as a comparison. Neither is exact for an individual.
How many calories should I eat to lose weight?
A common starting point is TDEE minus 250 to 500 kcal a day, which is roughly 0.25–0.5 kg (about 0.5–1 lb) of weight change a week. Do not go below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision.
Is the 3,500-calorie rule accurate?
It is a useful approximation, not a law. Your metabolism adapts as you lose weight, so progress usually slows. Treat the weekly change shown as a first estimate and recalibrate with real weigh-ins.
How are the macros worked out?
Your calorie target is multiplied by the percentage chosen for each macro, then divided by 4 kcal per gram for protein and carbohydrate and 9 kcal per gram for fat. The three amounts add back up to your target.
Does this calculator give medical advice?
No. It is an educational estimate. For weight, medical conditions or eating-disorder concerns, speak to a doctor or registered dietitian.
Sources and further reading
- Mifflin et al. (1990), “A new predictive equation for resting energy expenditure” — PubMed
- NHS — Understanding calories
- NIH NIDDK — Adult overweight and obesity
Reviewed September 26, 2026 by the SolveCalcPro editorial team. Found a mistake? Tell us; see our editorial policy.