What is TDEE?
Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in 24 hours. It bundles four components: your basal metabolic rate (the calories you burn at complete rest), the thermic effect of food (calories spent digesting), your non-exercise activity (NEAT — fidgeting, walking, posture), and exercise itself. For cutting purposes, your TDEE is the baseline — the number you eat below to lose fat.
This calculator uses the Mifflin-St Jeor equation — the most accurate predictive RMR formula for healthy adults across multiple validation studies (Frankenfield et al. 2005). The Harris-Benedict equation, which you'll still see in older calculators, consistently overestimates by 5–15% in modern populations.
How TDEE is calculated
Two steps. First, the Mifflin-St Jeor equation estimates your basal metabolic rate (BMR):
Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Then BMR is multiplied by an activity multiplier to estimate TDEE:
- Sedentary (1.2×) — desk job, no formal exercise
- Light (1.375×) — light exercise 1–3 days/week
- Moderate (1.55×) — moderate exercise 3–5 days/week (most lifters)
- Very Active (1.725×) — intense exercise 6–7 days/week
- Extremely Active (1.9×) — physical job + daily training
The output is an estimate, not a measurement. Use it as a starting point, then track weight for 2–3 weeks and adjust calories ±100–150 based on actual scale movement.
Picking your deficit
The calculator surfaces three deficit tiers — mild, moderate, and aggressive — based on your TDEE. The right choice depends on your timeline and how much fat you have to lose:
- Mild (~10%) — for body recomp or final 1–2 kg cuts. Slow but sustainable.
- Moderate (~20%) — the productive default for most cuts of 4–10 kg.
- Aggressive (~25%+) — for short-duration "mini-cuts" or higher body fat starts.
Aggressive deficits accelerate fat loss but compromise strength and recovery — the Roth 2022 review on training-during-energy-restriction is unambiguous that intensity preservation depends on adequate fuel. See the maintaining strength during a cut guide for the full case.
Common questions
What is TDEE?
Total Daily Energy Expenditure — the total calories your body burns in a day, including basal metabolic rate (BMR), thermic effect of food, and physical activity. Knowing your TDEE is the first step to setting a cutting calorie target.
Which TDEE formula is most accurate?
The Mifflin-St Jeor equation is widely considered the most accurate predictive equation for resting metabolic rate in healthy adults — multiple validation studies show it outperforms Harris-Benedict and Katch-McArdle in non-athlete populations. This calculator uses Mifflin-St Jeor.
What activity level should I pick?
Most people overestimate. If you train 3–5 times a week with otherwise sedentary office work, "Moderate" (1.55x) is usually correct. Pick "Very Active" (1.725x) only if you train 6+ days a week or have a physical job. When in doubt, choose the lower option — under-estimating TDEE and adjusting up is safer than the reverse.
How big should my cutting deficit be?
For most lifters, 15–25% below TDEE is the productive range. A moderate 20% deficit (around 400–500 kcal/day for the average UK adult) loses ~0.5–0.75 kg/week without significant muscle loss when protein and training are managed. Aggressive cuts above 25% accelerate fat loss but compromise strength and recovery — see the Roth 2022 evidence in the maintaining-strength-during-a-cut guide.
How often should I recalculate TDEE?
Every 4–6 weeks during a cut, or after every 2–3 kg of weight change. As bodyweight drops, BMR drops with it (smaller body = lower energy needs). Failing to recalculate is the most common reason people stall on what feels like the same deficit.
Is this calculator accurate for women?
Yes — Mifflin-St Jeor was validated in both men and women across a range of body compositions. Select "Female" in the sex field for the correct equation. Note that menstrual-cycle-driven water retention can shift scale weight by 1–2 kg without any actual fat-loss change.
Sources
- Mifflin MD, St Jeor ST et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. PubMed
- Frankenfield D, Roth-Yousey L, Compher C (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. Journal of the American Dietetic Association. PubMed
- Roth C et al. (2022). Training Volume and Intensity during Energy Restriction: A Narrative Review for Resistance-Trained Athletes. Sports Medicine — Open. PMC
- Trexler ET, Smith-Ryan AE, Norton LE (2014). Metabolic adaptation to weight loss: implications for the athlete. Journal of the International Society of Sports Nutrition. PMC