forme
← All posts

4 June 2026

How to calculate your TDEE, and use it to lose weight

Your TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day. You calculate it in two steps: work out your BMR (Basal Metabolic Rate) using the Mifflin-St Jeor formula, then multiply by an activity factor. To lose weight, you eat a few hundred calories below your TDEE. Here is the full method with an example.

What is TDEE?

TDEE is everything your body uses energy on in a day: keeping you alive at rest (your BMR), digesting food, moving around, and exercise. It is the single most useful number for weight goals, because eating below it loses weight, eating at it maintains, and eating above it gains.

Step 1: calculate your BMR

The Mifflin-St Jeor equation is the most accurate widely used formula. It uses weight in kilograms, height in centimetres and age in years.

For example, a 35 year old man, 80 kg and 180 cm: 10 × 80 + 6.25 × 180 − 5 × 35 + 5 = 800 + 1125 − 175 + 5 = 1755 kcal.

Step 2: multiply by your activity level

Activity levelWhat it meansMultiplier
SedentaryDesk job, little exercise1.2
Lightly activeLight exercise 1 to 3 days a week1.375
Moderately activeExercise 3 to 5 days a week1.55
Very activeHard exercise 6 to 7 days a week1.725
Extremely activePhysical job or training twice a day1.9

Our 1755 kcal example, lightly active: 1755 × 1.375 = about 2410 kcal. That is the TDEE.

Try it with your own numbers

TDEE calculator

Sex

Age

yrs

Height

cm

Weight

kg

Activity level

Goal

MAINTENANCE (TDEE)

2,711 kcal / day

YOUR DAILY TARGET TO LOSE WEIGHT

2,210 kcal

144 g

Protein

265 g

Carbs

64 g

Fat

At this target you would lose about 0.5 kg a week, a steady, safe pace.

Get this tracked for you

forme sets this target automatically, then tracks your calories and macros from a quick scan, led by a personal food score. No maths, no logging every gram.

How do you turn TDEE into a weight loss target?

Subtract a calorie deficit. About 7700 kcal equals 1 kg of fat, so a deficit of roughly 500 kcal a day loses about 0.5 kg a week, which is a steady, sustainable pace. From a 2410 kcal TDEE, a weight loss target would be around 1900 kcal a day.

A few rules keep it safe:

Is the number exact?

No, and it does not need to be. Every formula is an estimate, and real expenditure varies day to day with steps, sleep and stress. Treat your TDEE as a starting target, then adjust based on what the scale trend actually does over two to three weeks.

Skip the maths, get your number

forme works out your TDEE from your stats and goal, sets a safe calorie and macro target, and shows the date you are on track to hit. From a quick onboarding.

Let forme do it

Doing this by hand is fine once. The harder part is keeping the target accurate as you go and tracking your day against it. forme calculates your TDEE during onboarding, turns it into a daily calorie and macro target with a safe deficit, projects when you will reach your goal weight, and then tracks each day from a quick scan rather than manual logging.

The bottom line

Calculate TDEE in two steps: BMR with Mifflin-St Jeor, then an activity multiplier. Eat a few hundred below it to lose weight, recalculate as you go, and adjust to the scale trend rather than trusting the formula blindly. This is food guidance to help you reach your own goals, not medical or dietary advice.

Be first to forme

We are putting the finishing touches on forme. Leave your email and we will tell you the moment it is ready.

No spam. Just one note when we are ready for you.