TDEE Calculator

What this TDEE calculator does

This calculator estimates your Total Daily Energy Expenditure — the number of calories your body burns over a full 24-hour day, including everything from breathing to your evening run. It uses the Mifflin-St Jeor equation to compute basal metabolic rate (BMR) from your sex, age, height and weight, then multiplies by a standard activity coefficient (the same 1.2 / 1.375 / 1.55 / 1.725 / 1.9 ladder that nutrition and exercise textbooks use) to produce TDEE. The result is your maintenance calorie number — eat that amount in a typical day and your weight should stay the same.

How to use the calculator

1. Pick metric or imperial units.
2. Enter your sex, age, height and weight.
3. Pick the activity level that matches an average week (not your best week). The dropdown shows the multiplier and a short description for each tier.
4. Read the headline TDEE in kcal/day. The BMR (resting) and the activity multiplier are shown alongside so you can see the working.
5. Tap Copy summary to put the full result on your clipboard.

BMR vs TDEE — the two-step calculation

Energy expenditure has two layers. The bottom layer is BMR: the fixed cost of running a human body at rest. It scales with body size (taller and heavier bodies cost more to run), decreases gently with age (about 1–2 % per decade after age 30), and runs a touch higher in males because of the lean-mass difference at population level. The top layer is activity: the cost of moving — both deliberate exercise and the subconscious motion that makes up most of your day. Multiplying BMR by an activity factor folds all that motion into one number.

The Mifflin-St Jeor formula itself is straightforward:

• Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
• Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161

Multiply the result by your activity multiplier and you have TDEE.

Activity level — what each tier really means

The mismatch between the tier you’d like to claim and the tier that matches your week is the single biggest source of TDEE error. Concrete examples help:

• Sedentary (× 1.2). Desk job, little or no deliberate exercise. Walking to the kitchen counts as life, not exercise. Most knowledge workers who don’t train are here, even those who feel “busy”.
• Light (× 1.375). 1–3 deliberate sessions a week. A couple of evening walks plus one yoga class. A weekend hike. Two short gym visits with a long Sunday rest.
• Moderate (× 1.55). 3–5 sessions a week of meaningful exercise — resistance training, structured cardio, sport practice. This is the realistic home of most “regular” exercisers.
• Heavy (× 1.725). Hard training 6–7 days a week. Two-a-week long-duration sessions plus daily shorter ones, or a manually demanding job that has you carrying and lifting most of the shift.
• Athlete (× 1.9). Twice-a-day blocks during a competitive in- season, or a manual job where you’re under load eight hours a day — framing, roofing, lumber, professional moving, military field work.

When in doubt, drop one level. People consistently over-estimate.

Why TDEE estimates are population-level

Mifflin-St Jeor was fitted to a real-world cohort of nearly 500 healthy adults. The equation describes that cohort well — within ±10 % for about 80 % of cases. But individual variation always exceeds the formula’s resolution. ±200–300 kcal/day of person-to-person difference is normal, driven by:

• Lean-mass to fat-mass ratio. BMR scales with metabolically active tissue, which the equation only approximates from total weight. A muscular athlete reads low against measured RMR; a less active person reads high.
• Thyroid function. Sub-clinical hypothyroidism can drop measured RMR several percent.
• NEAT. Non-exercise activity thermogenesis — fidgeting, posture changes, standing, pacing — ranges several hundred kcal per day between high- and low-NEAT individuals doing the same job.
• Adaptive thermogenesis. A long history of dieting modestly lowers measured TDEE at a given weight.

This is why nutrition coaches treat any calorie target as a starting hypothesis and adjust based on what the scale and the mirror say over two to three weeks.

When to use TDEE — and when to look beyond it

TDEE is the right tool for planning daily intake, sanity-checking a meal-prep calorie target, picking a starting point for a deficit or surplus, or estimating what counts as “a lot of food” for someone of your build. If you want a specific deficit or surplus number, look at the calorie-calculator which scales TDEE down or up for weight goals, and the macro-calculator for the protein/carbohydrate/fat split.

For genuine precision — clinical nutrition, athletic peaking, eating- disorder recovery — ask for indirect calorimetry at a sports-med clinic. A 15-minute mask test gives RMR within ±2 %, and a follow-up DEXA scan gives the body composition that explains the residual gap between the predicted and measured TDEE.

Privacy

This calculator does its arithmetic in JavaScript on your device. There is no fetch call, no analytics on the values you enter, no server-side logging. The page works the same way offline once loaded.