Enter your details and click Calculate
to see your daily calorie needs.
Enter your age, sex, height, weight, and activity level, then click Calculate My Calories. The calculator returns your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — and your Total Daily Energy Expenditure (TDEE) — your real-world daily calorie burn based on how active you are. You'll also see estimated macro targets split across protein, carbohydrates, and fat, plus weight goal calorie targets for losing, maintaining, or gaining weight. Switch between Imperial and Metric units at any time. No account or signup required — all calculations run instantly in your browser.
This calculator uses the Mifflin-St Jeor equation, developed in 1990 by M.D. Mifflin and S.T. St Jeor. It is considered the most accurate BMR formula for most adults and is preferred by the Academy of Nutrition and Dietetics over the older Harris-Benedict equation (1919), which tends to overestimate calorie needs by 5% on average.
The formulas are: For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5. For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. The +5 and −161 constants account for sex-based differences in lean body mass and basal metabolism. Higher weight and height increase BMR, while older age decreases it — reflecting the well-documented slowing of metabolism with age.
BMR (Basal Metabolic Rate) is the number of calories your body needs to sustain life at complete rest — breathing, circulation, organ function, temperature regulation, and cell repair. It represents roughly 60–70% of total daily calorie burn for most people. BMR is what you'd burn if you stayed perfectly still in bed all day.
TDEE (Total Daily Energy Expenditure) is your real-world calorie burn, calculated by multiplying BMR by an activity factor. TDEE is the number that actually matters for nutrition planning. Eat at your TDEE to maintain your current weight. Eat consistently below it to lose weight. Eat consistently above it to gain weight. BMR alone is useful for understanding your baseline metabolism, but TDEE is your actionable daily calorie target.
The activity multiplier is the most impactful variable in the TDEE calculation, and it's the one most people get wrong — typically by overestimating how active they are. Here's how to choose accurately:
Sedentary (×1.2) — Desk job, minimal movement outside of work, no structured exercise. Most office workers fall here even if they "walk around the office." Lightly Active (×1.375) — Light cardio or strength training 1–3 days per week, otherwise mostly seated. Moderately Active (×1.55) — Consistent exercise 3–5 days per week at moderate intensity, plus a reasonably active daily life. This is the most common category for people who regularly work out. Very Active (×1.725) — Hard training 6–7 days per week, or a moderately active job combined with regular gym sessions. Extra Active (×1.9) — Elite athletes, manual labor workers who also train, or military personnel in active duty. This level is often overestimated. When in doubt, choose the lower option and adjust based on real-world results over 2–4 weeks.
This calculator uses a 30/40/30 split — 30% of calories from protein, 40% from carbohydrates, and 30% from fat — as a starting point. This balanced split supports muscle retention, sustained energy, and healthy hormone function for most adults. Converting from calories to grams: protein and carbohydrates each provide 4 calories per gram, while fat provides 9 calories per gram. A 2,000-calorie diet on this split would mean approximately 150g protein, 200g carbs, and 67g fat.
The 30/40/30 split is a reasonable general starting point, but optimal macros vary by goal. Higher protein (35–40%) supports muscle building and fat loss by preserving lean mass. Lower carb, higher fat approaches (like ketogenic diets) shift the ratio dramatically toward fat. Work with a registered dietitian if you have specific medical or performance goals.
The foundational principle of weight management is energy balance. One pound of body fat contains approximately 3,500 calories. A daily calorie deficit of 500 calories below your TDEE creates roughly 3,500 calories of deficit per week — theoretically about 1 pound of fat loss. A 1,000 calorie/day deficit leads to approximately 2 pounds per week. This is the theoretical maximum most experts recommend for sustainable fat loss without significant muscle loss.
Most nutrition experts recommend a floor of 1,200 calories/day for women and 1,500 calories/day for men without medical supervision. Below these thresholds, it becomes difficult to get adequate protein, vitamins, and minerals, and the body may adapt by lowering metabolic rate — making further fat loss harder. For weight gain, a surplus of 250–500 calories/day supports muscle growth with minimal excess fat accumulation. Individual variation is significant: factors like gut microbiome, sleep quality, stress hormones, and medication can all affect how your body responds to a given calorie intake.
Expert guides and educational resources to help you master the math.
A 500-calorie daily deficit produces roughly 1 lb/week — but your actual target depends on TDEE. Here's the Mifflin-St Jeor formula, activity multipliers, and why everyone eventually hits a plateau.
BMI = (weight lbs × 703) ÷ height inches². But it doesn't measure fat, muscle, or fat distribution — and uses different risk thresholds for different ethnicities. Here's what it means and what to measure instead.
