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BMI & Daily Calorie (TDEE) Calculator

Calculate your BMI with the standard and South Asian cut-offs, your basal metabolic rate and daily calorie needs for your activity level, and a healthy weight range for your height.

0 BMI
Category—
Healthy weight range for your height—
Basal metabolic rate (Mifflin-St Jeor)—
Daily calories to maintain weight (TDEE)—
To lose ~0.5 kg a week—
To gain ~0.25 kg a week—
Suggested protein—

In short

BMI = weight in kg ÷ height in m². For South Asian adults the WHO and NICE action points are 23 (overweight) and 27.5 (obese) instead of 25 and 30. Daily calorie needs = Mifflin–St Jeor BMR (10 × kg + 6.25 × cm − 5 × age + 5 for men / − 161 for women) × an activity factor of 1.2–1.9; a 500 kcal daily deficit loses about 0.5 kg a week.

Who this is for: Adults checking BMI with the South Asian cut-offs and setting a daily calorie target.

Not tax or legal advice. General health information, not medical advice. BMI and calorie estimates are screening tools; pregnant women, children, older adults and people with medical conditions should follow a doctor's or dietitian's guidance.
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BMI, BMR and daily calories explained

  • BMI = weight (kg) ÷ height (m)². Standard WHO categories: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese. For South Asian adults the WHO and UK NICE advise lower action points — 23 for overweight and 27.5 for obese — because the risk of type 2 diabetes and heart disease rises at a lower BMI; this calculator defaults to those.
  • BMR (basal metabolic rate) uses the Mifflin–St Jeor equation: 10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women) — the calories your body burns at complete rest.
  • TDEE (total daily energy expenditure) = BMR × activity factor (1.2 sedentary to 1.9 very active). Eating about 500 kcal below TDEE loses roughly 0.5 kg a week; 250 above gains about 0.25 kg, mostly as muscle if you train.
  • Protein at 1.2–1.6 g per kg of body weight supports muscle retention during weight loss; general guidance is 0.8 g/kg.

BMI is a screening number, not a diagnosis: it does not account for muscle, bone density, age or where fat is carried. Waist circumference and waist-to-height ratio add useful context.

Assumptions

  • BMI = kg ÷ m²; categories at 18.5 / 23 / 27.5 (South Asian, default) or 18.5 / 25 / 30.
  • BMR by Mifflin–St Jeor; TDEE = BMR × activity factor; loss = TDEE − 500, gain = TDEE + 250.
  • Protein range 1.2–1.6 g per kg of current weight.

Worked example

35-year-old man, 170 cm, 78 kg, light activity

BMI = 78 ÷ 1.70² = 27.0 — "overweight" on the South Asian scale (and on the standard scale). Healthy range for 170 cm: 53.5–66.5 kg (South Asian) — about 11.5 kg above.
BMR = 10×78 + 6.25×170 − 5×35 + 5 = 1,673 kcal; TDEE at 1.375 = 2,300 kcal; to lose 0.5 kg a week eat about 1,800 kcal with 94–125 g protein.

Frequently asked questions

Why are the cut-offs lower for South Asians?

Research shows people of Pakistani, Indian and Bangladeshi background develop diabetes and cardiovascular disease at lower BMIs, so WHO and NICE set action points at 23 and 27.5 instead of 25 and 30.

Is BMI accurate for athletes?

No — muscle is denser than fat, so muscular people can show as overweight. Use body-fat percentage or waist-to-height ratio instead.

How many calories should I eat to lose weight in Ramadan?

Your TDEE does not change with fasting hours; keep the same daily total across iftar, dinner and suhoor and avoid making up the deficit with fried food and sugary drinks.

How accurate is the calorie estimate?

Mifflin–St Jeor is within about 10% for most adults. Track your weight for two to three weeks and adjust by 100–200 kcal if it is not moving as expected.

What is a healthy BMI for South Asians?

18.5 to 22.9 under the WHO lower cut-offs; 23 and above is overweight and 27.5 and above obese.

How many calories should I eat a day?

Your TDEE — BMR × activity factor — typically 2,000–2,600 kcal for men and 1,600–2,100 for women; subtract 500 to lose about 0.5 kg a week.

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