Free Tool
TDEE Calculator: Your Maintenance Calories and BMR
Before any diet number makes sense, you need the number it is measured against. This calculator gives you your BMR, your TDEE, and the honest deficit that loses fat without losing muscle. No email needed.
By Luke Thomas, NASM-CPT. Updated September 2026.
Calculate your BMR and TDEE
Your BMR is what your body burns lying still all day. Your TDEE adds your real life on top. Enter your numbers and pick the activity level that describes a normal week, not your best one.
Your daily burn
The breakdown:
Your number above is the target. Hitting it is about protein, fiber and sleep first. If appetite is the hard part for you, LEAN is the support I recommend alongside those habits.
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Next step: turn your calories into protein, carb, and fat targets
BMR, TDEE, and why the difference matters
Your basal metabolic rate is the energy your body spends keeping you alive at complete rest: heartbeat, breathing, brain, body temperature, cell repair. For most women it is somewhere between 1,200 and 1,600 calories a day, and it is the biggest single piece of your daily burn.
The calculator uses the Mifflin-St Jeor equation, which has held up as the most accurate of the common formulas for the general population, including women over 40.
Total daily energy expenditure takes your BMR and multiplies it by how much you actually move: your workouts, yes, but also walking, chores, fidgeting, and the energy it takes to digest food. This is the number diets should be built from, because a deficit only exists relative to it.
Eat at your TDEE and you maintain. Eat 250 to 500 below it and you lose about half a pound to a pound a week, which is the pace where what you lose is fat rather than muscle.
Three truths about your metabolism
Muscle is your metabolic insurance
Every pound of muscle nudges your BMR up and, more importantly, keeps it from sliding down with age. The single best thing a woman over 40 can do for her TDEE is lift something heavy twice a week.
Non-exercise movement outweighs workouts
A 45-minute workout burns 300 calories. A day of walking, standing, cooking, and errands can burn 500 to 800. The difference between two women with the same BMR is usually the invisible movement, not the gym.
Starving lowers the number you are trying to beat
Eat far below your BMR for long and your body adapts: less fidgeting, colder hands, lower thyroid output, muscle lost. The deficit shrinks under you. A modest gap you can hold beats a heroic one you cannot.
TDEE questions, answered
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest, roughly 60 to 70 percent of your total. TDEE is BMR plus everything you do all day: exercise, walking, chores, and digesting food. TDEE is the number to plan your eating around.
How accurate is a TDEE calculator?
Within about 10 percent for most people, which is 150 to 200 calories either way. Treat it as a starting point: eat at the number for two weeks, watch your weight trend, and adjust by 100 calories at a time until the scale does what you want.
Which activity level should I choose?
The one that describes a normal week, including the weeks you skip the gym. Most people should pick one level lower than their first instinct. If you have a desk job and train three times a week, lightly active is usually closer than moderately active.
How many calories should I eat to lose weight?
Start 250 to 500 calories below your TDEE. That produces roughly half a pound to a pound a week, which is the pace research consistently links to keeping muscle and keeping the weight off. My calorie calculator turns that into a full plan with a goal date.
Does TDEE go down after 40 or after menopause?
A little, and mostly because of muscle loss and less daily movement rather than age itself. Research suggests metabolism is remarkably stable from 20 to 60 when you account for body composition. Keep your muscle and your steps, and your TDEE largely keeps itself.
Should I eat below my BMR to lose faster?
No. Eating below your BMR for more than a few days tells your body it is starving, and it responds by burning muscle and dialing down everything it can. The minimum I coach is 1,200 calories for women and 1,500 for men, and most people do better well above that.
Your Next Step
The number is easy. The habits are the work.
Your TDEE tells you the target. The free 14-Day No-Gimmicks Weight-Loss Reset shows you how to hit it without counting every bite, one simple habit a day. Same coach, same no-gimmicks approach.
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Practical health and fitness for women who want to feel strong at any age. Coached by Luke — NASM-certified (CPT, CES, PES) with 20+ years in the field.