BMR Calculator

How the BMR calculation works

BMR is the estimated energy cost of staying alive before daily movement, training, and digestion are added. This page uses the Mifflin-St Jeor equation because it is widely used in nutrition tools and tends to perform reasonably for general adult populations. It still cannot see lean mass, thyroid status, medication effects, or dieting history.

For lifters, BMR is useful because it separates baseline physiology from activity. If two athletes have the same BMR but one trains five days per week and works a physical job, their maintenance calories will be very different. Use BMR as the floor, then use TDEE to choose an eating target.

A low BMR result does not mean your metabolism is broken. It usually reflects body size, age, sex, and height. The actionable number is not BMR by itself; it is the calorie intake that keeps bodyweight, training performance, and recovery moving in the direction you want.

• BMR is before activity
• TDEE is BMR plus activity
• Medical conditions require qualified guidance

Practical example

If you are using the BMR Calculator, enter the most repeatable inputs you have, write down the result, then check it against two weeks of real training or bodyweight data. A calculator is useful when it gives you a starting number and a way to adjust, not when it pretends one formula can remove uncertainty.

Limitations

e1RM calculators are planning tools for healthy adults. They do not replace medical advice, coaching judgment, federation rules, or lab testing. Use conservative inputs when recovery is poor, technique is changing, or the result would push you into loads you have not recently handled.