BMR Calculator

Your Basal Metabolic Rate (BMR) is the number of calories your body would burn if you stayed in bed all day doing absolutely nothing. It's the energy your organs need just to keep you alive: heart pumping, lungs inflating, cells regenerating, brain running. Roughly 60–75% of your daily calorie burn is BMR — that's how dominant it is.

Knowing your BMR is the first step to building a calorie target for any goal — losing fat, gaining muscle, or maintaining. Combine it with an activity multiplier to get TDEE (your real daily burn), then create a deficit or surplus from there. See the TDEE Calculator for the next step.

30-year-old man, 80 kg (176 lb), 180 cm (5'11"), Mifflin-St Jeor:

• BMR = (10 × 80) + (6.25 × 180) − (5 × 30) + 5
• BMR = 800 + 1,125 − 150 + 5 = 1,780 calories/day
• Per hour: 1,780 ÷ 24 ≈ 74 cal/hr

A sedentary day adds ~20% (TDEE ≈ 2,136). A moderately active day adds ~55% (TDEE ≈ 2,759). To lose ~1 lb/week, eat about 500 calories below TDEE.

• Setting a daily calorie target for fat loss, muscle gain, or maintenance.
• Understanding why eating "normally" causes weight gain — many people simply eat above TDEE without realizing it.
• Planning a refeed or diet break — eating at TDEE for a week can restore hormones during a long cut.
• Tracking changes over time — recalculate as you lose or gain weight.
• Building meal plans — knowing the floor helps avoid eating dangerously low.

• Treating BMR as your daily target. BMR is the floor; TDEE is your actual burn. Eating only at BMR is an aggressive cut.
• Overestimating activity level. Most people overestimate by one tier. If you have a desk job and gym 3×/week, you're likely "light" or "moderate", not "very active".
• Not adjusting after weight change. Lose 30 lb and your BMR drops with you — recalculate.
• Ignoring body composition. Two people at the same weight can have BMRs 200+ calories apart depending on muscle mass.
• Trusting a single number forever. BMR formulas have a margin of ±10%. Track real-world results and adjust.