NumberTally Calorie Calculator — Daily Calorie Needs (TDEE)
Estimate your daily calorie needs with the Mifflin-St Jeor equation. Get your BMR, your TDEE at all five activity levels, and calorie targets for losing, maintaining, or gaining — with your projected pounds per week.
Advanced options
Adds the Katch-McArdle BMR (based on lean mass) for comparison.
Added on top of your goal preset. Use −250 for a slower cut, for example.
BMR vs TDEE — which number actually matters
Your BMR (basal metabolic rate) is what you’d burn lying in bed all day — the cost of keeping your organs running. Your TDEE (total daily energy expenditure) is BMR plus real life: walking, working, exercising, even digesting food. This calculator estimates BMR with the Mifflin-St Jeor equation, then multiplies by an activity factor to get TDEE.
For weight goals, TDEE is the number that counts: eat below it and you lose, above it and you gain. BMR is mostly useful as a floor — most sustainable plans keep intake at or above it.
Why 500 calories a day ≈ 1 pound a week
A pound of body fat stores roughly 3,500 kilocalories. Eat 500 fewer per day and the weekly deficit is about 3,500 — roughly a pound. It’s a rule of thumb, not physics: water shifts, muscle changes, and metabolic adaptation all nudge the real number. That’s why the fine-tune box exists — start at −500, watch the scale for two weeks, then adjust.
Estimates only — not medical advice. Talk to a healthcare professional before a major diet change.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is the calories you burn at complete rest just staying alive. TDEE is BMR plus daily movement, exercise, and digestion. This page estimates BMR with Mifflin-St Jeor, then applies your activity factor — the step-by-step box shows both.
How accurate is the Mifflin-St Jeor equation?
It’s among the best-validated formulas for the general population, usually within about 10% of lab-measured values. Muscle mass, medical conditions, and medications can shift your true number — entering body fat % gives the lean-mass-based Katch-McArdle check.
Why does the weight-loss preset subtract 500 calories?
500 kcal/day × 7 days ≈ 3,500 kcal, roughly a pound of fat per week. It’s a moderate, sustainable starting deficit — the fine-tune box lets you soften it to −250.
Should I ever eat below my BMR?
Your BMR is the cost of staying alive at rest, so eating below it long-term can leave you under-fueled. Most plans keep intake at or above BMR and build the deficit through activity instead. Talk to a professional before going very low.
Do I need to recalculate as my weight changes?
Yes — a lighter body burns fewer calories, so a target that worked at your old weight can stall at the new one. Recalculate every 5–10 lb lost or gained, or about monthly while changing.