Which calorie equation is most accurate?

For most people, Mifflin–St Jeor provides a strong baseline. If you know your body fat %, Katch–McArdle can better reflect lean mass and often improves accuracy.

Do I need to count calories exactly?

No. Use the target as a starting point. Track your progress for 2–3 weeks and adjust by 5–10% based on weight and energy levels.

Are the activity multipliers evidence-based?

They reflect widely used Physical Activity Level ranges consistent with FAO/WHO/UNU guidance and common sports-nutrition practice.

Is the tool suitable for teens, pregnancy, or medical conditions?

This tool is for healthy adults. Needs differ during pregnancy, for teens, older adults, and people with medical conditions—consult a qualified clinician.

How are macros calculated?

By default: protein 1.6 g/kg, fat 0.8 g/kg (minimum), and remaining calories go to carbs. You can customize protein per kg if desired.

What rate of weight change is safe?

Typical guidance: lose 0.25–1.0% of body weight per week, gain 0.25–0.5% per week. Extreme deficits or surpluses are discouraged.

Do you store my data?

No. Calculations run in your browser and are not sent to any server.

Calorie Calculator | Health and Fitness

Data Source and Methodology

Mifflin–St Jeor (1990): Mifflin MD, St Jeor ST. “A new predictive equation for resting energy expenditure in healthy individuals.” American Journal of Clinical Nutrition. 1990;51(2):241–247. PubMed
Harris–Benedict (revised 1984): Roza AM, Shizgal HM. “The Harris Benedict equation reevaluated.” American Journal of Clinical Nutrition. 1984;40(1):168–182. PubMed
Katch–McArdle: Katch VL, McArdle WD. “Nutrition, Weight Control, and Exercise.” 1983–1996 editions. Common formulation: BMR = 370 + 21.6 × lean mass(kg).
Activity multipliers (PAL): Consistent with commonly applied ranges aligned to FAO/WHO/UNU energy requirement frameworks. See FAO/WHO/UNU Expert Consultation (2004). FAO

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

BMI: $\\displaystyle BMI=\\frac{\\text{weight (kg)}}{\\left(\\frac{\\text{height (cm)}}{100}\\right)^2}$

Mifflin–St Jeor:

$\\displaystyle BMR_{male}=10W+6.25H-5A+5 \\quad\\; BMR_{female}=10W+6.25H-5A-161$

Harris–Benedict (revised):

$\\displaystyle BMR_{male}=88.362+13.397W+4.799H-5.677A$

$\\displaystyle BMR_{female}=447.593+9.247W+3.098H-4.330A$

Katch–McArdle: $\\displaystyle BMR=370+21.6\\times LBM$, where $LBM=W\\times (1-\\tfrac{BF}{100})$

TDEE: $\\displaystyle TDEE=BMR\\times PAL$

Goal target: $\\displaystyle kcal_{target}=TDEE\\times (1+\\Delta)$ where $\\Delta$ is −0.10, −0.20, −0.25, +0.10, +0.20, or 0.

W = weight (kg), H = height (cm), A = age (years), BF = body fat (%), PAL = activity multiplier.

Glossary of Variables

Sex at birth Required for Mifflin and Harris–Benedict; affects BMR constants.

Age Years, adults only (14–80 supported in this tool).

Height Body height in centimeters (or feet/inches converted to cm).

Weight Body mass in kilograms (or pounds converted to kg).

Body fat % Optional; enables Katch–McArdle via lean mass.

BMR Basal Metabolic Rate: energy at complete rest.

TDEE Total Daily Energy Expenditure: BMR × activity multiplier.

Protein/Fat/Carbs Daily macronutrient targets based on selected rule.

BMI Body Mass Index; screening metric, not a diagnosis.

Weekly change Estimated weekly weight change from daily surplus/deficit (≈ 7700 kcal per kg).

Worked Example

How It Works: A Step-by-Step Example

Inputs: male, 30 years, 175 cm, 72 kg, Moderate activity (1.55), Mifflin–St Jeor, Maintain.
Compute BMR (male): BMR = 10·72 + 6.25·175 − 5·30 + 5 = 720 + 1093.75 − 150 + 5 = 1668.75 ≈ 1669 kcal.
TDEE = 1669 × 1.55 ≈ 2587 kcal.
Maintenance target = 2587 kcal/day. Protein (1.6 g/kg) = 115 g (460 kcal). Fat (0.8 g/kg) = 58 g (522 kcal). Carbs = (2587 − 460 − 522)/4 ≈ 401 g.
BMI = 72 / (1.75²) ≈ 23.5.

Your own results will differ based on your profile and chosen goal.

Frequently Asked Questions (FAQ)

How accurate are calorie calculators?

They provide estimates. Individual energy needs vary with genetics, NEAT (non-exercise activity), hormones, and measurement error. Track outcomes and adjust by 5–10%.

Should I use Katch–McArdle if I know my body fat?

Often yes. It reflects lean mass and can improve precision, especially for people with higher or lower body fat than average.

What if my weight isn’t changing?

Average your scale weight 3–4 days per week for 2–3 weeks. If stable, adjust calories by ~150–250 kcal/day and reassess.

Can I set very aggressive deficits?

We limit presets to −25% as a safety guard. Larger deficits can harm performance, recovery, and micronutrient intake. Seek clinical advice before extreme changes.

Do macros matter as much as calories?

Calories drive weight change. Adequate protein supports satiety and lean mass; fats support hormones; carbs fuel training. Choose a sustainable distribution.

Where can I learn more about daily calorie needs?

See an accessible overview from the BBC: How many calories do you need?

Tool developed by Ugo Candido. Content verified by Registered Dietitian (RD) reviewers. Last reviewed for accuracy on: September 14, 2025.