How to Calculate Your TDEE for Weight Loss or Gain

Your TDEE (Total Daily Energy Expenditure) tells you how many calories you burn each day — sitting on the sofa, walking to the shops, or at the gym. Calculate it, and you know exactly how many calories to eat to lose weight, maintain, or build muscle.

Calculate your TDEE with our TDEE calculator. You'll need your age, height, weight, and typical activity level. It takes 30 seconds. Everything after this is the "why" and "how" — the calculator gives you the number.

What Is TDEE?

Your TDEE is the sum of four things:

1. BMR (Basal Metabolic Rate) — calories your body burns at complete rest, just keeping your heart, lungs, and organs running. For a typical adult, this is 1,200–1,800 calories per day depending on size and sex.
2. NEAT (Non-Exercise Activity Thermogenesis) — calories burned moving through daily life: walking, fidgeting, climbing stairs, carrying shopping. This varies wildly (100–1,000 calories per day) depending on your job and habits.
3. EAT (Exercise Activity Thermogenesis) — calories burned in deliberate exercise: running, weights, cycling. A 30-minute jog burns 250–400 calories depending on your weight and pace.
4. TEF (Thermic Effect of Food) — calories burned digesting food itself. Protein requires the most energy (~25% of calories eaten), then carbs (~5%), then fat (~0%). Eating 2,000 calories costs roughly 150–300 of those calories just to digest.

Add these four together, and you have your TDEE. Most tracking apps and calculators (including ours) use a formula that estimates it based on activity level — not because measuring it precisely is impossible, but because doing it accurately requires lab equipment. The Mifflin-St Jeor equation is the industry standard and usually accurate to within 10–15%.

How TDEE Affects Weight Loss

This is where it gets practical. Your body can't violate thermodynamics: to lose weight, you must eat fewer calories than you burn. But "fewer" doesn't mean starvation.

A deficit of 300–500 calories per day produces fat loss of 0.25–0.5kg per week — slow enough that you don't feel wrecked, fast enough to see progress. The science of calorie deficits explains why smaller deficits are often easier to stick to than aggressive ones.

Example scenario: You calculate your TDEE at 2,200 calories per day. To lose weight steadily, eat 1,700–1,900 calories daily. After 2 weeks, weigh yourself daily and average the week — if the trend is flat, drop another 150–200 calories. If you're losing 0.3kg per week, stick with it. The maths works.

Most people also underestimate how much walking burns. A 30-minute walk burns 100–200 calories depending on your weight and pace — not huge, but meaningful over a week. NHS physical activity guidelines recommend 150 minutes of moderate activity weekly; that's roughly 1,000–1,500 extra calories burned per week just from moving.

Don't obsess over the number. TDEE is a starting point, not a law. Your actual calorie burn varies by 10–15% day to day based on weather, stress, sleep quality, hormones, and how much you fidget. Eat within 100–200 calories of your target and trust the week-to-week trend.

Building Muscle: TDEE Plus a Surplus

Muscle growth requires two things: a slight calorie surplus, and resistance training (weights, not cardio).

Eat at TDEE + 200–300 calories per day with adequate protein. Protein needs for muscle scale with body weight — aim for 1.6–2.2g per kilogram of body weight daily. If you weigh 80kg, that's 130–180g of protein per day.

Train with weights 3–4 times per week, focusing on compound movements (squats, deadlifts, bench press, rows). Progressive overload — gradually increase reps, sets, or weight — is what signals your body to build muscle.

Expect realistic gains:

• Beginner (first 6–12 months): 0.5–1kg of muscle per month
• Intermediate (1–3 years): 0.25–0.5kg per month
• Advanced (3+ years): 0.1–0.25kg per month (if that)

A surplus of 200–300 calories is deliberate: more than that, and you'll gain more fat than muscle. This is why "bulk then cut" is standard — you can't optimise for both at once.

Practical: Tracking and Adjusting

Start with a baseline. Use our TDEE calculator, then measure every 4–8 weeks (not weekly — weight fluctuates day to day due to water, food volume, and hormones, which creates noise).

For weight loss: Track what you eat. A food scale and an app like MyFitnessPal take the guesswork out. After 2 weeks, if you're not moving toward your goal, adjust by 200 calories. You don't need to be perfect — within 100–200 of your target is close enough.

For muscle gain: Track your workouts. Stronger = more muscle (roughly). If you're not getting stronger, either eat more or train harder.

For general health: The specifics matter less than consistency. 150 minutes of moderate activity per week plus 2+ strength sessions, 7–9 hours of sleep, and 2+ litres of water daily outweigh almost any diet hack. Sleep directly affects weight management, recovery, and whether your deficit feels sustainable or miserable.

If you're optimising macros, use our macro calculator to split your calories across protein, carbs, and fat. Setting realistic goals also helps — losing 0.5kg per week is sustainable; losing 1kg per week is harder to maintain, even if it's technically possible.

Frequently Asked Questions

Q: Can I calculate my TDEE exactly without a calculator? A: No — not without a metabolic chamber (a lab instrument that measures every calorie you burn). Equations like Mifflin-St Jeor and Katch-McArdle are estimates. They're usually within 10–15% of reality, which is close enough for practical use. The calculator does this for you.

Q: Does TDEE change? A: Yes. If you gain or lose weight, your TDEE changes (heavier people burn more calories). If you build muscle, your BMR increases slightly (muscle is metabolically expensive). Extreme dieting for months can suppress NEAT and reduce your TDEE by 10–20%, which is why "metabolic adaptation" feels real — it is, at least partly.

Q: What if I eat below my TDEE but don't lose weight? A: Either (a) you're eating more than you think (scales lie, portion estimates are often 20% off), (b) your TDEE is lower than calculated (individual variation, especially after prolonged dieting), or (c) it's only been a week (noise). Measure weekly averages over 4 weeks before assuming the equation is wrong.

Q: Is TDEE the same as basal metabolic rate (BMR)? A: No. BMR is just resting metabolism. TDEE adds activity on top. Your BMR might be 1,500 calories; your TDEE (with a desk job and a gym session) might be 2,200.

Q: How do activity levels in the calculator work? A: Most calculators use multipliers:

• Sedentary (little or no exercise): TDEE = BMR × 1.2
• Lightly active (exercise 1–3 days/week): TDEE = BMR × 1.375
• Moderately active (exercise 4–5 days/week): TDEE = BMR × 1.55
• Very active (exercise 6–7 days/week): TDEE = BMR × 1.725
• Extremely active (physical job or twice-daily training): TDEE = BMR × 1.9

If your job is sedentary but you train hard, you're between categories — adjust accordingly.

Q: If I'm not losing weight on my calculated TDEE, what do I do? A: Drop your calorie target by 150–200 calories and try again for 2–3 weeks. Then reassess. Repeat until you see a 0.3–0.5kg per week trend. This beats guessing.

Q: Does my TDEE account for my body fat percentage? A: The standard formulas (Mifflin-St Jeor) don't. They assume an "average" body composition for your age, height, and weight. If you're very muscular, your TDEE is slightly higher. If you carry more fat, it's slightly lower. Measuring body fat gives you a fuller picture, but for most people, the estimate is good enough to start.

Q: What's the difference between TDEE and calories? A: TDEE is measured in calories. It's the total amount. "Calories" as a unit applies to food and activity — a banana is ~100 calories, a 30-minute run burns ~300 calories (depends on your weight and pace). TDEE tells you how many total calories you burn in a day.

The Bottom Line

Your TDEE is a number, not a destiny. It's a starting point. Calculate it, eat near it (within 100–200 calories), measure your progress weekly, and adjust by 200 calories every 2–3 weeks if needed. The specifics vary — some people lose weight at 1,800 calories per day, others at 2,200 — but the principle stays the same: deficit = loss, surplus = gain, maintenance = stability.

Track for long enough (4–8 weeks) to see a clear trend, and you'll know exactly what your body needs.