Calculate your daily calorie needs (TDEE) based on age, weight, height, and activity level using the Mifflin-St Jeor formula.
Your daily calorie needs depend on your Basal Metabolic Rate (BMR) — the calories your body needs at complete rest — multiplied by an activity factor to get your Total Daily Energy Expenditure (TDEE). We use the Mifflin-St Jeor equation, the most accurate formula for most people:
Multiply BMR by your activity factor: 1.2 (sedentary), 1.375 (light exercise 1–3 days/week), 1.55 (moderate 3–5 days), 1.725 (heavy 6–7 days), 1.9 (very heavy / physical job + training) to get TDEE.
For weight loss: Eat 500 calories below TDEE to lose approximately 1 lb (0.45 kg) per week. For weight gain: eat 300–500 above TDEE. The minimum safe calorie intake is generally 1,200/day for women and 1,500/day for men.
Most calculators use the Mifflin-St Jeor equation to estimate basal metabolic rate (BMR): for men, 10×weight(kg) + 6.25×height(cm) − 5×age + 5; for women the same minus 161. BMR is then multiplied by an activity factor from 1.2 (sedentary) to 1.9 (very active) to give total daily energy expenditure (TDEE).
A 30-year-old woman, 165 cm and 65 kg, has a BMR of about 1,395 kcal. Moderately active (factor 1.55), her TDEE is roughly 2,160 kcal per day. A gentle 0.25–0.5 kg/week loss would target roughly 250–500 kcal below that.
Are these numbers exact? No — equations carry ±10% error and individual metabolism varies. Track real-world weight change over 2–3 weeks and adjust.
Is 1,200 kcal a safe floor? Very low targets risk nutrient deficiencies; consult a professional before aggressive deficits.
The formulas and figures used by this calculator come from these published sources. Where a figure changes from year to year, the year it applies to is stated on the page.
This tool provides general information only and is not medical advice. For questions about your own health, speak to a qualified healthcare professional.