How Many Calories Should You Eat Per Day? (2026 Guide)
How Many Calories Do You Actually Need?
Your daily calorie needs are not a fixed number. They depend on your age, sex, height, weight, and — most significantly — how active you are. The right figure is called your Total Daily Energy Expenditure (TDEE): the total calories your body burns in a 24-hour period across all activities. Eat consistently at your TDEE and your weight stays stable. Eat below it and you lose weight. Eat above it and you gain.
The Mifflin-St Jeor Equation
The most accurate formula for estimating daily calorie needs is the Mifflin-St Jeor equation, endorsed by the American Dietetic Association and validated across diverse populations. It calculates your Basal Metabolic Rate (BMR) — the calories your body burns at rest — which is then multiplied by an activity factor to estimate TDEE.
For men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
For women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
Activity Multipliers
| Activity Level | Multiplier | Example |
|---|---|---|
| Sedentary | × 1.2 | Desk job, no exercise |
| Lightly Active | × 1.375 | Exercise 1–3 days/week |
| Moderately Active | × 1.55 | Exercise 3–5 days/week |
| Very Active | × 1.725 | Hard exercise 6–7 days/week |
| Extremely Active | × 1.9 | Twice-daily training / physical job |
Calorie Targets by Goal
Weight loss: Aim for 500 calories below your TDEE per day. This creates a weekly deficit of 3,500 calories — enough to lose approximately 0.45–0.5kg of fat per week. This rate is widely endorsed as safe and sustainable, minimising muscle loss while allowing consistent progress.
Muscle gain: Eat 200–300 calories above your TDEE per day. A modest surplus maximises muscle gain while minimising fat accumulation. Larger surpluses accelerate fat gain without proportionally increasing muscle growth rate.
Maintenance: Eat at your TDEE. Weight stays stable. This is the baseline from which all other strategies are built.
Important: Never eat below your BMR without medical supervision. The floor for safe caloric restriction is approximately 1,200 calories for women and 1,500 calories for men.
Why Calorie Calculators Are Only Estimates
TDEE formulas are accurate within approximately 10 percent for most people — meaning a calculated TDEE of 2,000 calories could reflect a true TDEE of 1,800–2,200 calories. Individual variation in gut microbiome, hormonal status, non-exercise activity thermogenesis (NEAT), and metabolic efficiency all affect real-world calorie needs.
The practical fix: use the calculator as a starting point, then observe your weight over 2–3 weeks. If weight isn't changing as expected, adjust by 100–200 calories in the appropriate direction.
Frequently Asked Questions
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References & Sources
- Mifflin, M.D. et al. (1990). A new predictive equation for resting energy expenditure. American Journal of Clinical Nutrition, 51(2), 241–247.
- Hall, K.D. et al. (2012). Quantification of the effect of energy imbalance on bodyweight. The Lancet, 378(9793), 826–837.
- Thomas, D.M. et al. (2014). Effect of dietary adherence on the body weight plateau. American Journal of Clinical Nutrition, 100(4), 1024–1031.