How Many Calories Do I Need Per Day? TDEE Calculator Guide

Key Fact — Updated May 2026

Total Daily Energy Expenditure (TDEE): TDEE is the total number of calories your body burns in a day, accounting for your Basal Metabolic Rate (BMR) — the energy used at complete rest — multiplied by your activity level. It is the most important number for anyone trying to lose, gain or maintain weight, as eating consistently below or above your TDEE determines your direction of travel.

How to calculate your TDEE

TDEE is calculated in two steps:

Step 1 — Calculate your BMR using the Mifflin-St Jeor equation (the most validated formula):

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

Step 2 — Multiply by your activity factor:

Activity Level	Description	Multiplier
Sedentary	Desk job, little exercise	× 1.2
Lightly active	1–3 days exercise per week	× 1.375
Moderately active	3–5 days exercise per week	× 1.55
Very active	6–7 days hard exercise	× 1.725
Extra active	Physical job + training	× 1.9

How to use your TDEE to reach your goal

Once you know your TDEE, the path to your goal is straightforward in principle:

Lose weight: Eat 300–500 calories below your TDEE per day. A 500 calorie daily deficit creates approximately 3,500 calories per week — roughly equivalent to 0.5kg (1lb) of fat loss.
Gain muscle: Eat 200–300 calories above TDEE in a controlled surplus. Too large a surplus leads to excess fat gain alongside muscle.
Maintain weight: Eat at TDEE. This is your maintenance level.

Example — 35 year old male, 80kg, 178cm, moderately active

BMR = (10 × 80) + (6.25 × 178) − (5 × 35) + 5 = 800 + 1,112.5 − 175 + 5 = 1,742.5 kcal. TDEE = 1,742.5 × 1.55 = approximately 2,701 kcal/day. For 0.5kg/week fat loss: target 2,201 kcal/day.

Why TDEE changes over time

TDEE is not fixed. It adapts as your weight, muscle mass and activity change:

As you lose weight, your BMR decreases — meaning your TDEE also drops. You may need to recalculate every 4–6 weeks.
Increased muscle mass raises your BMR — one reason resistance training is valuable for long-term weight management.
Significant calorie restriction causes metabolic adaptation — the body becomes more efficient and burns fewer calories, sometimes called 'starvation mode'.

Frequently Asked Questions

How many calories should I eat per day to lose weight?

Eat 300–500 calories below your TDEE per day. A 500 calorie daily deficit equates to roughly 0.5kg of fat loss per week. Deficits larger than 500–700 calories per day increase the risk of muscle loss and metabolic adaptation.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — purely to maintain organ function, breathing and temperature. TDEE multiplies your BMR by an activity factor to account for movement and exercise throughout the day.

Is 1,200 calories a day enough?

For most adults, 1,200 calories is below their BMR — meaning the body is consuming fewer calories than it needs for basic organ function. Very low calorie diets (VLCDs) should only be followed under medical supervision. A moderate deficit of 300–500 below TDEE is safer and more sustainable.

How accurate are TDEE calculators?

TDEE calculators are estimates based on population averages. Individual variation in metabolism means actual TDEE can differ by 10–15%. Track your weight weekly for 3–4 weeks eating at your calculated TDEE — if weight is changing, adjust your intake accordingly.

Calculate your TDEE now

Use the free CalcHubUK TDEE calculator — enter your stats and get your daily calorie target for your goal.

Use TDEE Calculator →