Your daily calorie requirement is the number of calories your body needs to maintain its current weight at a given level of activity. Knowing this value is the foundation of every effective diet — whether your goal is weight loss, maintenance or muscle gain. In this guide we show how to calculate it on your own.
From BMR to TDEE
The calculation consists of two stages. First we determine BMR (Basal Metabolic Rate) — the basal metabolism, that is the calories needed to sustain life at rest. Then we multiply BMR by an activity multiplier to obtain TDEE (Total Daily Energy Expenditure) — the total daily energy expenditure.
The Mifflin-St Jeor Formula
This is currently the most accurate and most frequently recommended formula for BMR:
- Men: BMR = 10 × weight[kg] + 6.25 × height[cm] − 5 × age[years] + 5
- Women: BMR = 10 × weight[kg] + 6.25 × height[cm] − 5 × age[years] − 161
Physical Activity Multipliers (PAL)
We multiply BMR by the multiplier that matches your lifestyle:
- 1.2 — sedentary lifestyle, no exercise
- 1.375 — light activity (1–3 workouts per week)
- 1.55 — moderate activity (3–5 workouts)
- 1.725 — high activity (6–7 workouts)
- 1.9 — very high activity (physical work or training twice a day)
Step-by-Step Example
Woman: 30 years old, 65 kg, 168 cm, moderate activity.
- BMR = 10 × 65 + 6.25 × 168 − 5 × 30 − 161
- BMR = 650 + 1050 − 150 − 161 = 1389 kcal
- TDEE = 1389 × 1.55 = 2153 kcal
To maintain her weight, this person needs about 2150 kcal per day. For weight loss you usually subtract 300–500 kcal (a deficit), and for muscle gain you add a similar amount (a surplus).
Calorie Deficit and Surplus
To lose weight, you need to consume fewer calories than your TDEE. A safe rate of weight loss is 0.5–1 kg per week, which corresponds to a deficit of 500–1000 kcal per day. Too aggressive a deficit slows the metabolism and leads to muscle loss. For muscle gain, a surplus of 250–500 kcal allows you to gain mostly muscle rather than fat.
Common Mistakes
- Overestimating your activity level (most people are less active than they think)
- Underweighing portions and ignoring liquid calories
- Sticking to the outdated Harris-Benedict formula instead of Mifflin
- Not adjusting after a change in weight — TDEE falls as your weight drops
Remember
Formulas give an estimate accurate to within about 10%. The best verification is observing your body weight over 2–3 weeks and adjusting calories if needed. In the case of metabolic conditions, consult your nutrition plan with a doctor or dietitian.
Don't want to calculate by hand? Our calorie needs calculator on liczbnik.pl will determine your BMR and TDEE after you enter a few details — along with a calorie suggestion for weight loss and muscle gain.