Calorie Calculator
Estimate your daily calorie needs for maintaining, losing, or gaining weight based on your activity level.
Reviewed October 7, 2026 Runs in your browser — inputs are never stored
This tool provides general educational estimates only and is not medical advice. It does not diagnose, treat, or replace guidance from a qualified healthcare provider. Consult a doctor for decisions about your health.
About the Calorie Calculator
A calorie calculator is a daily-nutrition tool that estimates how many calories you need to maintain, lose, or gain weight based on your body and activity level. It is built for anyone managing their diet — people working toward a weight goal, athletes fuelling training, fitness coaches building meal plans, and health-conscious users who want a clear daily target. Using the Mifflin-St Jeor equation for basal metabolic rate and an activity multiplier, the calculator returns your maintenance calories (TDEE) plus deficit and surplus targets for gradual weight loss or gain. By showing the maths behind the number, it helps you understand why the figure changes with activity and body composition, rather than offering a black-box result. Whether you are starting a cut, bulking cleanly, or simply maintaining, the tool gives you a reliable, private starting point that you can adjust as your progress evolves. For personalised medical or clinical dietary advice, always consult a registered dietitian or healthcare professional.
How to use it
- 1Enter age, sex, height, and weight.
- 2Pick the activity level that matches a typical week (be honest).
- 3Calculate maintenance calories (TDEE) and optional deficit/surplus targets.
- 4Use the maintenance figure as a baseline for meal planning.
- 5Recalculate after meaningful weight or activity changes.
Worked example
a 30-year-old woman, 165 cm, 62 kg, moderately active. Mifflin-St Jeor BMR is roughly 1,340 kcal; with a 1.55 activity factor, TDEE is about 2,080 kcal. A gentle fat-loss target might be ~1,800 kcal. Overstating activity is the main reason online calorie targets feel “too high.”
How it works
How it works
Your BMR is multiplied by an activity factor to get maintenance calories (TDEE). A deficit of ~500 cal/day targets roughly 0.5 kg (1 lb) of weight loss per week.
Who it is for
People working toward a weight goal, athletes fuelling training, fitness coaches building meal plans, and health-conscious users who want a clear daily calorie target based on their body and activity.
Why it helps
Estimating calorie needs by guesswork leads to stalled progress; the Mifflin-St Jeor equation plus an activity factor gives a data-driven maintenance, deficit, and surplus target you can actually plan meals around.
Tips for better results
- Be honest about your activity level — overestimating it inflates your target and stalls weight loss.
- Start with a 250–500 kcal deficit for sustainable loss (~0.25–0.5 kg per week), not a crash diet.
- Recalculate every 2–3 kg of weight change, since your needs fall as you lose weight.
- Track real-world results for two weeks and adjust the target up or down based on the scale trend.
Common mistakes to avoid
- Overestimating activity level, which inflates maintenance calories and undermines a deficit.
- Treating the estimate as exact — individual metabolism varies by 10–15%, so adjust to real results.
- Mixing imperial and metric units (pounds with centimetres) in the same calculation.
- Setting an aggressive 1,000+ kcal deficit that risks muscle loss and rebound eating.
Frequently asked questions
A:A daily deficit of about 500 calories generally produces around one pound of loss per week.
A:They are estimates; individual metabolism varies. Adjust based on real-world results.
Reviewed for accuracy · Last updated October 7, 2026
Formulas follow recognised clinical references — including WHO BMI classifications, the Mifflin-St Jeor equation, and Naegele’s rule — and are periodically checked against published reference values.
CalcWisee Editorial Team
Calculator development and formula review
CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.
Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards
References & sources
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