Basal metabolic rate calculator by age, gender and weight
Basal metabolic rate is the energy your body spends at complete rest to run the brain, organs and basic cellular work. Our basal metabolic rate calculator takes sex, age, weight and height and returns two classic estimates side by side: the Mifflin-St Jeor calculator path and the Harris Benedict BMR path. A 30-year-old man at 80 kilograms and 180 centimeters lands near 1780 kcal by Mifflin, while the same inputs through Harris-Benedict read a little higher. Women at identical stats read lower because the equations encode body-composition differences, which the men women chart beside the results makes visual.
Harris Benedict versus Mifflin-St Jeor
Harris-Benedict dates to 1919 with a 1984 revision and remains quoted across textbooks, while Mifflin-St Jeor from 1990 validates better against modern calorimetry for most adults. Neither is perfect: both miss very muscular builds, and both need activity layered on top for real life. That is why this page keeps both visible instead of hiding one. When the two agree within 100 kcal, trust the average. When they diverge more, lean toward Mifflin for typical builds and confirm with two weeks of tracked intake.
BMR versus TDEE and resting metabolic rate visuals
BMR versus TDEE is the most searched confusion in this niche. BMR is rest only; TDEE multiplies BMR by activity from 1.2 sedentary to 1.9 athlete. The BMR versus TDEE comparison bar shows all three numbers together, and the resting metabolic rate visualizer doughnut splits TDEE into baseline plus activity burn. For the worked example above at moderate activity, 1780 BMR becomes 2759 TDEE, leaving about 979 kcal of daily movement. Sedentary selection collapses the gap to a few hundred, which explains why desk workers lose slowly on formulas built for active defaults.
Which formula is best for Indians and when to retest
For Indian adults the same hierarchy holds: Mifflin-St Jeor as default, Harris-Benedict for comparison, and Katch-McArdle on the TDEE page when body fat is known. South Asian builds with higher fat at the same BMI should treat results as upper estimates and validate with two weeks of scale data. Recalculate after 2 to 3 kilograms of change, new training blocks, illness or long travel. The history log under vc-history-bmr-calculator stores each run with inputs so drift is visible across months rather than guessed.
Reports, mobile use and limits
The Download BMR Report button embeds both charts, inputs, formula names and disclaimers into a branded PDF for coaches or clinics. Everything runs client-side with large inputs, bottom tabs and dark-mode charts that respect reduced motion. Static equations cannot capture thyroid disorders, medication effects, pregnancy or elite muscle mass, so treat outliers with professional testing. This tool is for educational purposes only and is not a substitute for professional medical advice. Always consult your doctor before aggressive deficits. Related vitals tools link to TDEE for macros, BMI for ranges and food tracking for intake.
Practical workflow with the TDEE page
Start here for the baseline, then open the TDEE calculator to convert baseline into meals. Hold protein near 2 grams per kilogram, set fat near 0.9, fill carbs with the remainder, and run the pair for two weeks before adjusting. Export both PDFs at the start of each phase so targets, dates and charts stay documented. Small consistent edits beat formula shopping, and the side-by-side history proves it.
Formula math shown step by step
Mifflin-St Jeor for men is 10 times weight plus 6.25 times height minus 5 times age plus 5. For the 80-kilogram, 180-centimeter, 30-year-old example that is 800 plus 1125 minus 150 plus 5, totaling 1780 kcal. For women the constant flips to minus 161, so a 65-kilogram, 165-centimeter, 30-year-old woman computes 650 plus 1031 minus 150 minus 161, about 1370 kcal. Harris-Benedict uses larger coefficients with 88.362 and 13.397 terms for men and 447.593 with 9.247 terms for women, which is why it usually reads 50 to 150 kcal higher on the same inputs. Seeing both bars together teaches more than either number alone.
BMR by age, gender and weight with activity multipliers
Age drags BMR down roughly 5 kcal per year per the Mifflin age term, weight lifts it 10 kcal per kilogram, and height adds 6.25 per centimeter, so tall young heavy men top the scale while short older light women anchor it. BMR by age gender weight therefore spans from near 1200 for small sedentary older women to over 2200 for large young athletic men before activity. Multiply by 1.2, 1.375, 1.55, 1.725 or 1.9 for the five activity tiers and the same baseline fans out across a 1000-calorie range. Pick the tier matching real weeks, not aspirational ones, then let the doughnut show how much of TDEE is burn versus baseline.