BMR Calculator
Estimate basal metabolic rate and compare maintenance calories by activity level.
Personal Details
Enter height, weight, age, sex, and optional body fat to estimate resting calorie needs.
Activity Context
BMR is a resting estimate. Choose an activity level to see how it translates into maintenance calories.
If known, this switches BMR to the Katch-McArdle estimate.
Need an estimate first? Use the Body Fat Calculator .
Your BMR Estimate
Resting calories before activity, with maintenance context for common activity levels.
Maintenance Calories by Activity
Compare TDEE estimates across common activity multipliers.
Resting Energy Starting Point
BMR estimates what your body burns at rest. Use the activity comparison to move from resting needs to a practical daily maintenance target.
How The BMR Calculator Works
The calculator estimates resting energy first, then shows how activity changes daily needs.
Mifflin-St Jeor
The default estimate uses weight, height, age, and sex. It is a common starting formula for general adult calorie planning.
Katch-McArdle
When body fat percentage is entered, the calculator estimates BMR from lean body mass instead of total body weight.
Activity Context
BMR is not a full-day calorie target. Use the activity table to see how resting needs scale toward maintenance calories.
BMR vs TDEE
Use BMR for resting needs and TDEE for daily maintenance planning.
BMR is the baseline
BMR estimates resting energy needs before exercise, steps, work, digestion, and other movement are added.
TDEE is the daily target
TDEE multiplies BMR by activity. It is usually the better starting point for maintenance, weight-loss, or weight-gain planning.
BMR Calculator FAQ
Common questions about resting metabolism estimates.
What is BMR?
BMR is an estimate of the calories your body uses at rest for basic functions such as breathing, circulation, and temperature regulation.
Is BMR the same as TDEE?
No. BMR is resting energy use. TDEE adds daily movement and exercise by multiplying BMR by an activity factor.
Which BMR formula does this calculator use?
It uses Mifflin-St Jeor by default and switches to Katch-McArdle when a valid body fat percentage is supplied.