Calorie & BMR Calculator
Find your resting metabolic rate and daily calorie needs with the clinically validated Mifflin-St Jeor equation — with an optional Katch-McArdle body-composition mode, a 10% metabolic adjustment for Indian users, and a safe calorie plan for losing, maintaining or gaining weight.
About you
Advanced — body composition & localisation
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Your daily calorie targets
Maintenance is your TDEE. Deficits and surpluses are capped at safe, sustainable rates — roughly 0.25–0.5 kg per week.
BMR, RMR and TDEE — what they mean
Your Basal Metabolic Rate (BMR) is the minimum energy your body burns at complete rest — powering your heart, lungs, brain and cell repair — measured after a fast, with no activity. It typically accounts for 60–75% of the calories you burn each day. Resting Metabolic Rate (RMR) is a close cousin, usually about 10% higher because it includes small everyday movements. Your Total Daily Energy Expenditure (TDEE) is BMR scaled up by how active you are — and it is the number that actually matters for planning your diet, because it is your maintenance calorie level.
Why this tool uses Mifflin-St Jeor
Many calculators still run on the Harris-Benedict equation from 1919, which modern research shows overestimates BMR by roughly 5–15% in today's more sedentary adults — enough to stall weight loss because the deficit you think you have isn't really there. The Mifflin-St Jeor equation, published in 1990 and validated against indirect calorimetry, predicts resting metabolic rate within about 10% of measured values for most non-obese people and is the equation nutrition professionals now recommend. It is the default here.
Men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
Katch-McArdle for lean and muscular bodies
Mifflin-St Jeor's one limitation is that it uses total body weight and can't distinguish muscle from fat. A 95 kg person at 10% body fat has a much higher resting burn than a 95 kg person at 35% body fat, because muscle is metabolically active. If you know your body-fat percentage, the Katch-McArdle formula uses your lean body mass instead and is more accurate for athletic builds: BMR = 370 + (21.6 × lean body mass in kg). Turn on Advanced mode and enter your body-fat percentage to switch to it automatically.
The Indian metabolic adjustment
Just as BMI cut-offs differ for South Asians, so does metabolism. According to the ICMR, international equations tend to overestimate BMR for the Indian population by about 10–12%, largely due to differences in body composition. The optional adjustment in this tool multiplies your Mifflin-St Jeor BMR by 0.90, giving a more realistic baseline — precision that generic calculators simply don't offer.
Turning TDEE into a calorie plan
Your TDEE is worked out by multiplying BMR by an activity factor:
| Activity level | Multiplier | Typical profile |
|---|---|---|
| Sedentary | × 1.20 | Desk job, little movement |
| Lightly active | × 1.375 | Light exercise 1–3 days/week |
| Moderately active | × 1.55 | Moderate exercise 3–5 days/week |
| Very active | × 1.725 | Hard training 6–7 days/week |
| Extra active | × 1.90 | Physical job or twice-daily training |
A daily deficit of about 300–500 calories is linked to a safe, sustainable loss of roughly 0.25–0.5 kg per week. Bigger deficits are hard to keep up and tend to cost you muscle. The target matrix above deliberately caps deficits at this level and won't suggest eating below sensible minimums. Build the deficit from a balanced diet — plenty of vegetables, dals and whole grains, adequate protein — rather than crash dieting, and pair it with strength work to protect muscle.
Limitations to keep in mind
Every predictive equation is an estimate; true metabolic rate varies with genetics, hormones, sleep, medications and history of dieting. Use your calculated TDEE as a starting point, track your weight over two to three weeks, and adjust by 100–200 calories if the trend isn't moving as expected. For medical conditions, pregnancy, eating disorders or significant weight goals, work with a qualified professional.
Frequently asked questions
Why is Mifflin-St Jeor more accurate than Harris-Benedict?
Harris-Benedict (1919) overestimates BMR by about 5–15% in today's sedentary adults. Mifflin-St Jeor (1990) was validated against indirect calorimetry and lands within ~10% of measured values for most non-obese people, so it's the modern standard used here.
Should Indians reduce their BMR result?
The ICMR notes international equations overestimate BMR for Indians by ~10–12% due to body-composition differences. The optional adjustment here multiplies BMR by 0.90 for a more realistic baseline.
What's the difference between BMR and TDEE?
BMR is what you burn at complete rest (~60–75% of daily calories). TDEE is BMR × an activity factor — your maintenance calories, and the number to plan your diet around.
When should I use Katch-McArdle?
If you know your body-fat percentage. It uses lean body mass instead of total weight, so it's more accurate for lean or muscular people. Enter your body-fat % in Advanced mode to switch.
Why does BMR decrease with age?
Mainly sarcopenia — the gradual loss of calorie-hungry muscle as we age. Less muscle means a lower resting burn. Staying active and keeping muscle slows the decline.
How big a calorie deficit is safe?
About 300–500 calories a day, for roughly 0.25–0.5 kg lost per week. Avoid eating below ~1,500 kcal (men) or ~1,200 kcal (women) without supervision. This tool caps its suggestions there.