RMR Calculator
Estimate your resting metabolic rate with the revised Harris-Benedict equation, plus hourly burn and activity-adjusted daily needs.
Resting metabolic rate
1,672 kcal/day
Harris-Benedict (revised)
Per hour at rest
69.7 kcal
RMR ÷ 24 hours
Daily need with activity
2,591 kcal
RMR × activity factor
RMR is the energy your body uses at complete rest — roughly 60-75% of total daily burn. It is an estimate; actual needs vary with muscle mass, sleep and hormones.
RMR Calculator on True Calculator gives you an instant, accurate answer with no sign-up and no app install. Estimate your resting metabolic rate with the revised Harris-Benedict equation, plus hourly burn and activity-adjusted daily needs. Every result shows the formula and a worked example so you can verify the calculation yourself, and all values are computed in your own browser — your numbers never leave your device.
Popular uses: rmr calculator · resting metabolic rate calculator · resting calorie burn
How We Calculate
This calculator uses medically reviewed formulas verified by our team. All calculations are performed instantly in your browser using JavaScript — no data is sent to any server.
We use WHO-recommended formulas and medical standards for health calculations. Results are estimates, not medical advice — always consult a doctor for health decisions.
When to Use This Calculator
RMR is the foundation of almost every personal calorie plan. Weight-losers use it to size a safe deficit instead of guessing; gym-goers use the activity-adjusted figure to eat enough to build muscle; and people recovering from illness or surgery use it to make sure they meet basic energy needs. Nutritionists and dietitians in India routinely quote resting metabolic rate when advising clients on thyroid issues, PCOS and metabolic syndrome, because the resting burn anchors the whole diet. The per-hour figure is also handy for estimating standing, desk or bed-rest energy use. Since the revised Harris-Benedict equation was re-calibrated for modern body compositions, it is a reasonable first estimate for most adults between 20 and 80 — but it remains a population average, so real-world tracking is the final referee.
How to Use This Calculator
- Step 1: Select your sex — the revised Harris-Benedict equation uses different constants for men and women.
- Step 2: Enter your weight in kilograms, height in centimetres and age in years.
- Step 3: Pick the activity level that matches your typical week — sedentary for desk work up to very active for daily training.
- Step 4: Read your RMR, the per-hour resting burn, and the activity-adjusted daily need in the result cards.
Worked Example
A 30-year-old man weighing 70 kg at 170 cm gets an RMR of about 1,672 kcal per day — 88.362 plus 13.397 × 70 plus 4.799 × 170 minus 5.677 × 30. That works out to roughly 69.65 kcal per hour at rest. Choosing moderate activity multiplies the RMR by 1.55, giving a daily need of about 2,591 kcal. So if his actual food intake matches his activity honestly, that is the calorie level at which his weight stays roughly stable.
Tips and Common Mistakes
- •Tip 1: Weigh yourself in the morning after fasting for the most consistent inputs.
- •Tip 2: Recalculate every 5 kg of weight change — the equation is weight-sensitive.
- •Tip 3: Add resistance training to raise muscle mass, which quietly raises resting burn over time.
- ✗Mistake 1: Treating RMR as your full daily budget — daily needs include activity, so eating at RMR alone is a deficit.
- ✗Mistake 2: Double-counting exercise; the activity factor should describe your average week, not your best day.
Frequently Asked Questions
What is the difference between RMR and BMR?
Both measure the energy your body burns at rest. BMR is measured under strict fasting conditions right after waking, while RMR is measured under slightly less strict conditions and is usually a little higher. In daily use they are close enough that many formulas are used interchangeably.
Which equation does this calculator use?
It uses the revised Harris-Benedict equations (Roza & Shizgal, 1984) from 1984, which are more accurate for modern body compositions than the original 1919 version. Mifflin-St Jeor is another widely used alternative, but the two typically agree within about 5%.
How accurate is the RMR number?
Population equations are accurate to roughly ±10% for an individual, because muscle mass, thyroid function and genetics all shift the true value. Treat the result as a starting point: track weight for a few weeks and adjust calorie intake based on what actually happens.
What is RMR used for in weight management?
RMR is the base of your daily calorie budget. Multiplying RMR by an activity factor (1.2 for desk work up to 1.9 for heavy training) estimates total daily energy expenditure. Eating below that creates the deficit needed to lose weight; eating above it supports gain.
Does muscle mass change RMR?
Yes — metabolically active tissue raises resting burn, which is why two people of identical height, weight and age can have different RMRs. Resistance training that builds muscle gradually raises RMR, while severe calorie restriction can lower it as the body adapts.
Can I use RMR for Indian dietary needs?
Yes, the equations are population-neutral and widely validated in Indian adults. Indian diets are often carb-heavy and lower in protein, so if you use RMR for diet planning, pay attention to protein intake separately to preserve muscle while losing weight.
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