To calculate your TDEE by hand you need three numbers and two steps: estimate your BMR from sex, weight, height and age, then multiply by an activity factor. The whole thing fits on the back of an envelope, and the result is the same one our calorie calculator produces — this article just shows the working.

A day's energy use (illustrative)70%10%5%15%Resting (BMR)~70%Digestion (TEF)~10%Exercise (EAT)~5%Daily movement (NEAT)~15%Only BMR comes from an equation; the rest is the multiplier.Activity multiplier = base + NEAT shiftBASE · exercise days per week0 days/week× 1.201-3 days/week× 1.3754-6 days/week× 1.557+ days/week× 1.725NEAT SHIFT · daily movement outside trainingsedentary-0.05moderate0.00very active+0.10
Fig. Where a day's energy goes, as an illustrative split for a typical adult: resting metabolism (BMR) about 70%, the thermic effect of food (TEF) about 10%, exercise (EAT) about 5%, and non-exercise daily movement (NEAT) about 15%. The proportions vary widely between people — this is a teaching picture, not a measurement. Right: the activity multipliers the MacroDiet formula applies to BMR — exercise days per week set the base and the NEAT level shifts it — so TDEE = BMR × (base + NEAT shift).

Step 1 — BMR with Mifflin-St Jeor

The Mifflin-St Jeor equation was fitted to indirect-calorimetry measurements of 498 healthy adults aged 19–78, half of them women, half with obesity and half without1. It is the equation most modern calculators use, and it is ours.

SexBMR (kcal/day)
Men10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
Women10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

Use kilograms and centimetres. If you think in pounds and inches, convert first: kg = lb × 0.4536, cm = in × 2.54.

A useful sense of scale: each kilogram of body weight is worth 10 kcal of BMR, each centimetre of height 6.25 kcal, and each year of age costs 5 kcal. The sex term is a flat offset of 166 kcal between men and women of the same size and age.

Step 2 — the activity multiplier

Most calculators give you one "activity level" dropdown. We split it into two questions, because they measure different things:

QuestionAnswerValue
Training sessions per week01.2
1–31.375
4–61.55
7+1.725
Movement outside training (NEAT)sedentary — desk, car, sofa−0.05
moderate — some walking, some standing0
very active — on your feet most of the day+0.10

multiplier = training base + NEAT adjustment, so the possible range is 1.15 to 1.825. Then:

TDEE = round(BMR × multiplier)

Be honest with the training question. It counts sessions you actually do, not the ones on the plan. And "very active" NEAT means a job or life spent on your feet — postal rounds, nursing, construction, chasing toddlers — not a desk job with a standing desk.

Step 3 — check it against two weeks of real data

The formula gives a population estimate; your body is a sample of one. The only way to find out how close the estimate is, is to compare it with what happens when you eat around it.

For about two weeks, log what you eat and weigh yourself most mornings. Then look at the trend in weight, not any single reading. The arithmetic to turn a weight change into an expenditure correction is:

correction (kcal/day) ≈ weight change (kg) × 7,700 ÷ days

The 7,700 figure is the planning value the app uses for a kilogram of body fat. It is a rough constant, not a law — see is calories in, calories out true? — but over two weeks it is good enough to tell you the direction and the rough size of the miss.

Example: you ate an average of 2,800 kcal a day for 14 days aiming at a calculated TDEE of 2,837, and trend weight fell by 0.3 kg. Implied deficit: 0.3 × 7,700 ÷ 14 ≈ 165 kcal/day. Your expenditure was closer to 2,800 + 165 ≈ 2,965 than to 2,837. Small miss, in the normal range.

In plain terms: the formula gets you into the right neighbourhood; two weeks of data gets you to the right house.

Worked example

Male, 30 years, 180 cm, 85 kg, four to six training sessions a week, moderate NEAT.

  1. BMR: 10 × 85 = 850 · 6.25 × 180 = 1,125 · 5 × 30 = 150 → 850 + 1,125 − 150 + 5 = 1,830 kcal
  2. Multiplier: 1.55 + 0 = 1.55
  3. TDEE: 1,830 × 1.55 = 2,836.5 → rounds to 2,837 kcal/day

Had he answered "sedentary" for NEAT, the multiplier would be 1.50 and TDEE 2,745. Had he answered "very active", 1.65 and 3,020. The 275 kcal gap between those two answers is bigger than the gap between most competing BMR equations — which is why the second question matters.

Try the calculator

Our calorie calculator runs exactly this arithmetic in the browser (nothing you type is sent anywhere) and shows BMR, the multiplier and TDEE as separate lines so you can check the steps above against it. The macro calculator continues from the same TDEE to a protein, fat and carbohydrate split.

This is arithmetic, not a trial result. A population equation is typically 100–200 kcal off for an individual and can be 400–500 kcal off; the two-week check in step 3 is not optional if you want a number you can rely on.

The short version

BMR from Mifflin-St Jeor, times an activity multiplier built from training sessions and everyday movement, gives TDEE. For 85 kg, 180 cm, 30 years and 4–6 sessions a week that is 1,830 × 1.55 = 2,837 kcal. Then trust two weeks of logged intake and trend weight over the formula. Educational overview only — not medical advice.