TDEE & Nutrition Calculator
Estimate your daily calorie needs and a protein / fat / carb split that fits your goal.
How it works
TDEE is the total energy you burn in a day. It is built from two parts: the energy your body uses at complete rest (BMR), multiplied by a factor for how much you move.
BMR here uses the Mifflin-St Jeor equation, published in 1990 and generally considered the most accurate of the formulas that work from weight, height, age and sex. It replaced the older Harris-Benedict equation, which tends to overestimate by around 5%.
The activity multiplier is the least certain part and the part you choose yourself: 1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extremely active. Adjacent steps differ by 10–15% of TDEE — 250–350 kcal a day for a typical person. Picking one step too high turns a weight-loss plan into a maintenance plan.
The goal setting adds or subtracts 500 kcal a day. That number comes from the estimate that a kilogram of body fat is roughly 7,700 kcal, so a 500 kcal daily deficit gives about 0.45 kg a week — the rate usually considered sustainable.
Macros follow a simple rule: protein at 1.8 g per kg of body weight (enough to hold on to muscle in a deficit), fat at about 27.5% of calories, carbohydrate for the rest. This keeps muscle better than a fixed percentage split, which gives lighter people too little protein.
One caveat that matters: this is an estimate, not a measurement. For an individual it can be off by ±10%. Use it as a starting point, eat to it for two or three weeks, then adjust based on what the scale actually does.
Formula
BMR (male) = 10 × weight + 6.25 × height − 5 × age + 5 • BMR (female) = 10 × weight + 6.25 × height − 5 × age − 161 • TDEE = BMR × activity factor
Weight in kg, height in cm, age in years. The 166 kcal gap between the male and female constants reflects the average difference in lean mass at the same measurements.
Worked example
Male, 25, 170 cm, 65 kg, moderately active, maintaining:
- BMR
- 650 + 1,062.5 − 125 + 5 = 1,592.5 kcal
- Moderate activity factor
- × 1.55
- TDEE
- ≈ 2,468 kcal/day
- Protein (1.8 g/kg)
- 117 g
- Fat (27.5% of calories)
- 75 g
- Carbohydrate (remainder)
- 330 g
- To lose weight (−500)
- ≈ 1,968 kcal/day
Had this person picked "very active" (1.725) instead of "moderately active", TDEE would read 2,747 kcal — 279 higher, enough to turn a 0.45 kg-per-week plan into a 0.2 kg one.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is what your body burns lying completely still — breathing, circulation, body temperature. TDEE is BMR plus everything you do in a day, from walking around to training. Eating below BMR for extended periods is not advisable.
Which activity level should I pick?
One step below where you feel you belong. Most people overestimate, and 1.55 "moderately active" already means genuine training 3–5 days a week, not walking around an office.
Why a 500 kcal deficit?
A kilogram of body fat is roughly 7,700 kcal, so 500 a day gives about 0.45 kg a week. Larger deficits work faster for a few weeks but cost more muscle and are harder to sustain.
Why is protein set per kilogram rather than as a percentage?
Protein need tracks body mass, not calorie intake. A percentage split gives a light person eating few calories too little protein — exactly when they need it most to preserve muscle. 1.8 g/kg sits inside the 1.6–2.2 g/kg range the muscle-retention literature typically recommends.
How accurate is this?
For an individual, within about ±10%. The formula does not know your body composition, thyroid function or how much you fidget. Treat it as a starting point and adjust after two or three weeks of real data.
I am eating to my TDEE and nothing is happening. Why?
Usually the activity multiplier is one step too high, or intake is being under-recorded. Drop one activity step, give it two more weeks, and weigh yourself at the same time of day to strip out water noise.
Does this work for athletes?
It works, but Mifflin-St Jeor uses total body weight without separating muscle from fat, so it tends to read low for people carrying a lot of muscle. The Katch-McArdle equation, which is based on lean mass, suits that case better.