How to Calculate Your TDEE

Your Total Daily Energy Expenditure (TDEE) is an estimate of how many calories you burn in a typical day — everything from keeping your heart beating to walking to the shops to a session in the gym. It's the single most useful number for managing your weight. This guide shows exactly how it's calculated, with a worked example you can follow.

TDEE is a two-step calculation

TDEE isn't one formula, it's two steps:

1. Estimate your Basal Metabolic Rate (BMR) — the energy your body burns at complete rest, just running essential functions like breathing, circulation, and temperature regulation.
2. Multiply that BMR by an activity factor reflecting how much you actually move.

TDEE = BMR × activity multiplier

That's the whole structure. The interesting part is where each piece comes from.

Step 1: BMR, via Mifflin-St Jeor

We estimate BMR using the Mifflin-St Jeor equation, published in the American Journal of Clinical Nutrition in 1990:

Men:   BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

The two versions are identical except for the final constant. There are other BMR equations — the older Harris-Benedict being the best known — and the reason we use this one is covered in Why we use Mifflin-St Jeor.

If you only want this first number, the BMR Calculator gives it on its own.

Step 2: The activity multiplier

BMR only covers you at rest, so it's multiplied by a factor for daily activity:

This step is where most of the error creeps in, because you're picking a broad category rather than measuring anything. Choosing your activity level honestly covers how to pick well — it matters more than most people expect.

A worked example

Take a 30-year-old man, 170 cm tall, weighing 68 kg, who is sedentary.

Step 1 — BMR. Substitute into the men's equation:

(10 × 68) + (6.25 × 170) − (5 × 30) + 5
= 680 + 1062.5 − 150 + 5
= 1597.5 kcal

Step 2 — apply the multiplier. Sedentary means 1.2:

1597.5 × 1.2 = 1917 kcal/day

So his TDEE is roughly 1,917 kcal per day. That's what he'd need to eat to maintain his current weight.

For comparison, an otherwise identical woman would have a BMR of 1,431.5 kcal (the −161 constant instead of +5), giving a sedentary TDEE of about 1,718 kcal/day.

Our TDEE Calculator runs both steps for you and also converts from feet/inches and pounds if you prefer imperial.

What the number actually represents

TDEE is a daily average, not a fixed budget that resets at midnight. Real energy expenditure moves around from day to day — a long walk, a bad night's sleep, an illness — and that's normal. The number is most useful as a weekly average to plan around.

It's also an estimate, and honestly so. Individual metabolism varies by roughly ±10–15% for reasons the formula cannot see: body composition, genetics, hormones, sleep quality, and how much you fidget and move outside deliberate exercise. Two people matching on every input can genuinely need different amounts.

Where to go next

Once you have your maintenance number, using TDEE to lose or gain weight covers how to turn it into a target. If you want to know how those calories should be split between protein, carbs, and fat, the Macro Split Calculator takes your TDEE as its starting point, and the Protein Intake Calculator sets a protein target specifically.

The bottom line

TDEE = BMR × activity multiplier. The BMR half comes from a well-validated equation; the activity half is a judgement call you make, and it's the part most worth getting right. Calculate yours on the TDEE Calculator, which shows the formula source and confidence level alongside the result.