Estimate your daily calorie needs using the Mifflin-St Jeor equation. Enter your stats and activity level to see your Basal Metabolic Rate (BMR), maintenance calories, and recommended intake for your goal. Includes suggested macronutrient breakdown.
Daily calorie needs come from two pieces: Basal Metabolic Rate (BMR) — the calories your body burns just to keep the lights on — and the additional calories burned through movement, exercise, and digestion. Add them together and you get Total Daily Energy Expenditure (TDEE), which is the maintenance calorie level where your weight stays roughly constant.
This calculator uses the Mifflin-St Jeor equation, which has been validated in clinical studies as the most accurate predictive BMR equation for the general adult population. It multiplies BMR by an activity factor to estimate TDEE, then adjusts up or down based on your goal (lose, maintain, or gain weight).
Treat the output as a starting estimate. The Mifflin-St Jeor equation is typically accurate within ±10% for an individual — close enough to set a starting target, but you'll need to adjust based on what actually happens to your weight over 2–4 weeks. Real metabolic rate varies with muscle mass, hormonal status, recent dieting history, sleep, stress, and several other factors that no formula can capture.
40-year-old woman, 165 lb, 5'6", lightly active, wants to lose weight. Weight: 165 / 2.205 = 74.8 kg Height: 66 × 2.54 = 167.6 cm BMR = 10 × 74.8 + 6.25 × 167.6 − 5 × 40 − 161 = 1,434 kcal/day TDEE = 1,434 × 1.375 ≈ 1,972 kcal/day Weight-loss target: ≈ 1,472 kcal/day A 500-calorie deficit produces about 1 lb of weight loss per week, sustained over many weeks. Most healthy adults can sustain this without major hunger if protein intake stays high.
25-year-old man, 175 lb, 6'0", moderately active, wants to gain muscle. Weight: 175 / 2.205 = 79.4 kg Height: 72 × 2.54 = 182.9 cm BMR = 10 × 79.4 + 6.25 × 182.9 − 5 × 25 + 5 = 1,817 kcal/day TDEE = 1,817 × 1.55 ≈ 2,816 kcal/day Lean-gain target: ≈ 3,100–3,300 kcal/day For lean muscle gain, the surplus should be modest. Bigger surpluses just become fat. Combine with progressive resistance training and high protein intake (about 0.7–1g per pound of bodyweight).
Same 30-year-old male, 170 lb, 5'8". BMR is 1,705 kcal/day regardless of activity. Sedentary (office, no workouts): TDEE = 1,705 × 1.2 ≈ 2,046 Moderately active (4 workouts/week): TDEE = 1,705 × 1.55 ≈ 2,643 Very active (daily hard training): TDEE = 1,705 × 1.725 ≈ 2,941 The "activity bonus" alone is roughly 900 calories/day between sedentary and very active. Most weight management progress comes from the food side, but movement creates substantial headroom.
Use this calculator to set a starting calorie target when you're beginning a weight-loss, maintenance, or muscle-gain plan. The output is most useful as a baseline for tracking — eat at the target for 2–4 weeks, weigh weekly, and adjust based on the actual rate of change rather than trusting the formula blindly.
This calculator does NOT account for: - Pregnancy or lactation (significantly higher needs; consult a clinician) - Children and adolescents (use age-specific guidelines) - Athletes with very high training volumes (the activity factors top out at 1.9, but elite endurance athletes can burn far more) - Recovery from illness, surgery, or major metabolic conditions
For weight loss specifically, the standard "3,500 calories = 1 pound" rule is a simplification. Real fat loss includes water shifts, muscle changes, and metabolic adaptation; rate of loss usually slows over time even at the same deficit. A small additional deficit may be needed every 4–8 weeks during sustained dieting.
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Daily Target Calories
2,644 cal
Maintenance Calories
2,644 cal
Basal Metabolic Rate
1,706 cal
Goal
Maintain Weight