Calorie Calculator (TDEE)
Estimate your daily calorie needs with the Mifflin-St Jeor equation, then get targets to lose, maintain or gain weight with safe minimums and macro splits.
Verified October 2026 · Sources: Mifflin et al., Am J Clin Nutr 1990; Roza & Shizgal 1984; Harvard Health (calorie minimums); IOM Dietary Reference Intakes (macros)
TDEE = BMR × 1.55 = 2,711 kcal
Daily change = -0.5 kg × 7,700 kcal ÷ 7 = −550 kcal
Macros for your target
Within the IOM ranges (carbs 45–65%, protein 10–35%, fat 20–35%).
Compare goals
| Goal | Calories/day | Notes |
|---|---|---|
| Lose 0.75 kg/week | 1,886 kcal | −825 kcal/day |
| Lose 0.5 kg/week | 2,161 kcal | −550 kcal/day |
| Lose 0.25 kg/week | 2,436 kcal | −275 kcal/day |
| Maintain weight | 2,711 kcal | Your TDEE |
| Gain 0.25 kg/week | 2,986 kcal | +275 kcal/day |
| Gain 0.5 kg/week | 3,261 kcal | +550 kcal/day |
How activity changes your needs
| Activity level | Maintenance | Lose 0.5 kg/week |
|---|---|---|
| Sedentary (× 1.2) | 2,099 kcal | 1,549 kcal |
| Lightly active (× 1.375) | 2,405 kcal | 1,855 kcal |
| Moderately active (× 1.55) | 2,711 kcal | 2,161 kcal |
| Very active (× 1.725) | 3,017 kcal | 2,467 kcal |
| Extra active (× 1.9) | 3,323 kcal | 2,773 kcal |
BMR by formula
- Overstating activity — choose the level for a typical week, not your best week.
- Counting exercise twice: picking 'very active' and also eating back tracker calories.
- Not recalculating as you lose weight — your needs drop as your body gets smaller.
- Cutting too hard: very low intakes make it hard to get enough protein, fibre, vitamins and minerals.
- Judging progress day to day — water shifts hide fat loss; compare weekly averages over 2–4 weeks.
- →Track your weight for 2–4 weeks; if it isn't moving as expected, adjust by 100–200 kcal a day.
- →Prioritise protein, vegetables, fruit and whole grains to stay full on fewer calories.
- →Check your BMI and healthy weight range to set a realistic goal weight.
- →If you have a medical condition or take medication, ask your doctor or a registered dietitian before dieting.
This tool is for informational purposes only. Always verify results with a qualified professional.
What is the Calorie Calculator (TDEE)?
A calorie calculator estimates how much energy your body uses in a day so you can eat to maintain, lose or gain weight. It works in two stages. First it estimates your basal metabolic rate (BMR) — the calories you burn at complete rest to keep your heart, lungs, brain and organs working. Then it multiplies BMR by an activity factor to give your total daily energy expenditure (TDEE), also called maintenance calories. Eat about your TDEE and your weight should stay roughly stable; eat less and you lose weight, eat more and you gain.
This calculator uses the Mifflin-St Jeor equation by default. Published in the American Journal of Clinical Nutrition in 1990 and built from indirect calorimetry measurements on 498 healthy adults aged 19–78, it is generally considered the most accurate everyday equation for adults: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. You can switch to the revised Harris-Benedict equation (Roza and Shizgal, 1984), or — if you know your body fat percentage — the Katch-McArdle equation, BMR = 370 + 21.6 × lean body mass (kg), which can suit very lean or very muscular people better. The calculator shows all available results side by side so you can see how much they differ.
Worked example: a 30-year-old man who is 175 cm tall, weighs 80 kg and exercises moderately 3–5 days a week has a Mifflin-St Jeor BMR of 10 × 80 + 6.25 × 175 − 5 × 30 + 5 = 1,749 kcal. Multiplying by the moderate activity factor of 1.55 gives a TDEE of about 2,711 kcal a day. To lose about 0.5 kg a week he would aim for roughly 550 kcal less per day — around 2,161 kcal. With a balanced 50/20/30 split that is about 270 g carbohydrate, 108 g protein and 72 g fat.
To turn a weekly weight goal into a daily calorie change, the calculator uses the common approximation that 1 kg of body fat stores about 7,700 kcal, so 0.5 kg a week means a deficit of about 550 kcal a day. The NHS describes losing 0.5–1 kg a week as a safe, sustainable rate. Real weight loss usually slows over time as your body adapts, so treat the numbers as a starting point and adjust after a few weeks based on your actual progress.
Going too low is risky. Harvard Health advises that calorie intake should not fall below 1,200 a day for women or 1,500 a day for men except under the supervision of a health professional, because it becomes hard to get enough nutrients. If your chosen goal would take you below that, this calculator caps the target at the minimum and tells you the slower rate you'll actually achieve. These estimates are for healthy adults; they do not apply during pregnancy or breastfeeding, for teenagers, or for people with medical conditions that affect metabolism.
How to Use This Calculator
- 1Choose metric or imperial units, then enter your sex, age, height and weight.
- 2Optionally add your body fat % to unlock the Katch-McArdle equation (use our Body Fat Calculator if you don't know it).
- 3Pick the activity level that honestly matches a typical week — most office workers are sedentary or lightly active.
- 4Choose your goal: maintain, lose 0.25–0.75 kg a week, or gain 0.25–0.5 kg a week.
- 5Pick a macro split preset to see daily grams of carbohydrate, protein and fat.
- 6Compare the goal and activity tables, then track your weight for 2–4 weeks and adjust by 100–200 kcal if needed.