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Health & fitness

Calorie Calculator: BMR, TDEE & Macros

Daily calorie needs from the Mifflin-St Jeor equation, activity-adjusted, with protein/carb/fat gram targets for four common plans.

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Quick answer

BMR (Mifflin-St Jeor) = 10×kg + 6.25×cm − 5×age (+5 men, −161 women); daily need = BMR × activity factor (1.2 sedentary → 1.9 very active). A 25-year-old man, 70 kg, 175 cm, moderately active: ≈ 2,594 kcal to maintain.

Maintenance calories
2,594 kcal/day
BMR (at rest)
1,674 kcal/day
Mild cut (−15%)
2,205 kcal
Lean bulk (+10%)
2,854 kcal
Protein
195 g
Carbs · Fat
259 g · 86 g

Mifflin-St Jeor is the equation clinical dietitians use, but every formula is an estimate with roughly ±10% spread between individuals. Track your weight for two weeks at the suggested intake and adjust by 100–200 kcal, your own data beats any equation.

Formulas last verified 2026-10-10. Results are estimates, not financial advice. How we calculate.

From BMR to your actual day

BMR = 10×kg + 6.25×cm − 5×age (+5 men / −161 women)
TDEE = BMR × activity factor

A 25-year-old man at 70 kg and 175 cm: BMR = 700 + 1,093.75 − 125 + 5 = 1,674 kcal, what his body burns doing nothing. Moderately active (training 3–5 days a week), TDEE = 1,674 × 1.55 ≈ 2,594 kcal. Eat that and weight holds; the gap between any target and TDEE is the entire mechanism of weight change.

The activity factors, honestly assessed

LevelFactorActually means
Sedentary1.2Desk job, no regular exercise
Light1.3751–3 workouts a week
Moderate1.553–5 workouts a week
Active1.7256–7 workouts a week
Very active1.9Physical job plus training

Most people overrate this by one level, three gym visits a week with a desk job is "moderate", not "active". Overrating by one level inflates the target by ~300 kcal/day, which quietly erases a planned deficit.

Using the macro split

At 2,594 kcal on the balanced 30/40/30 plan: about 195 g protein, 259 g carbs and 86 g fat, the calculator prints the exact grams for each plan. The one macro worth prioritising for most goals is protein, around 1.6–2.2 g per kg of body weight when training, because it preserves muscle in a deficit and satiates per calorie better than the other two. Fill protein first, split the remainder by preference; adherence beats optimisation.

The two-week calibration

  1. Eat the maintenance figure, weigh daily, same conditions.
  2. Compare week-1 and week-2 averages. Flat → the number is your TDEE. Drifting → adjust 100–200 kcal and repeat.
  3. Re-run the calculator after every ~5 kg change, and when training volume shifts, the inputs moved, so the output did.

Pair with the BMI calculator for the screening picture, and, since consistency is a scheduling problem as much as a willpower one, the date calculator for tracking the weeks between check-ins.

Frequently asked questions

How are daily calorie needs calculated?

Two steps. BMR (energy at complete rest) via Mifflin-St Jeor: 10×weight(kg) + 6.25×height(cm) − 5×age, plus 5 for men or minus 161 for women. Then multiply by an activity factor from 1.2 (sedentary) to 1.9 (very active) to get TDEE, total daily energy expenditure, your maintenance calories.

Why Mifflin-St Jeor rather than Harris-Benedict?

Validation studies have repeatedly found Mifflin-St Jeor the most accurate of the common equations for modern populations, which is why clinical dietitians adopted it. Harris-Benedict (1919) tends to overestimate by roughly 5%. Even so, every equation is a population average, individual metabolisms spread about ±10% around it.

How big a deficit should I run to lose weight?

A moderate deficit of 15–20% below TDEE (roughly 300–500 kcal for most people) loses about 0.25–0.5 kg a week while remaining sustainable. Aggressive cuts backfire: adherence collapses, muscle loss rises, and metabolism adapts downward. The mild-cut figure the calculator shows is the evidence-aligned starting point.

What do the macro numbers mean?

Your calories split into protein and carbs (4 kcal per gram) and fat (9 kcal per gram). The plans are common templates: balanced 30/40/30, high-protein 40/35/25 (favoured while cutting, since protein preserves muscle and satiety), low-carb and keto. Total calories still decide weight change; macros shape body composition and hunger.

How accurate is this, really?

Good enough to start, not to finish. Equations carry ±10% individual spread, activity multipliers are self-assessed, and food logging errs 20%+. The honest method: eat the suggested maintenance for two weeks, track weight daily, average weekly, the trend is your true TDEE. Adjust 100–200 kcal at a time. Your own data beats any formula, including this one.

Is this medical advice?

No, it is arithmetic over published equations, for general information. Calorie needs shift with medical conditions, medications, pregnancy and age; for any of those, or a history of disordered eating, work with a doctor or registered dietitian rather than a calculator.

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