How to Calculate TDEE: 5 Steps to a Number You Can Trust

Calculating TDEE is one of those things that sounds harder than it is. With five simple steps you can land on a number that is accurate to within 5–10% of your true daily burn — and within four weeks you can refine that number to be near-perfect.

Step 1 – Pick a unit system you'll stick with

Mixing kilograms and pounds is the most common mistake. Decide on one system before you enter any data. Our calculators support both and switch instantly with one click.

Step 2 – Measure your inputs honestly

You need four numbers: sex, age, height, weight. Use your real morning weight (after the bathroom, before breakfast). For height, measure barefoot against a wall. Honesty here is non-negotiable; 2 cm or 2 lb of fudge translates into 50–80 kcal/day of error.

Step 3 – Choose a BMR formula

For 95% of adults, Mifflin-St Jeor is the most accurate option:

Men: BMR = 10W + 6.25H − 5A + 5
Women: BMR = 10W + 6.25H − 5A − 161

Where W = weight in kg, H = height in cm, A = age in years.

If you are very lean and athletic, Katch-McArdle is more accurate because it uses lean body mass directly:

BMR = 370 + 21.6 × LBM(kg)

Step 4 – Pick an activity factor — pessimistically

Most people overestimate activity by one full level. A 30-minute walk three times a week is "lightly active", not "moderately active". When in doubt, pick one rung lower than you think.

Quick reference:

Sedentary 1.2 — desk job + zero training.
Light 1.375 — desk job + 2–3 short workouts.
Moderate 1.55 — 3–5 quality workouts.
Very 1.725 — daily hard training.
Extra 1.9 — daily training plus a physical job.

Step 5 – Multiply (or just use the calculator)

Take BMR × activity factor. That's your TDEE estimate.

Or skip the math: use our free TDEE calculator. It runs three formulas in parallel, includes unit conversion, and shows targets for cutting, maintenance, and bulking — no sign-up.

Validation: the 14-day rule

Once you have a TDEE estimate, eat at it (within 100 kcal) for 14 days while logging weight every morning. Two outcomes:

Weight stable (±0.3 kg). Estimate is accurate.
Weight changed. Adjust by 100 kcal/day in the appropriate direction and run another 14 days. Or use our Adaptive TDEE tool to do the math automatically.

Common pitfalls

Using your goal weight, not your current weight. Always use the present-day number.
Forgetting to update. A 10 kg weight change moves TDEE by 100–200 kcal. Recalculate.
Choosing two activity levels above reality because of a couple of weekend hikes.
Trusting a single tracker reading. Wearables can be off by ±20%.

The bottom line

Five steps, one calculator, one number. That is your starting point. The fastest way to a better physique is to commit to the math, eat with intent, and verify with the scale every two weeks.