Calorie Calculator
Daily calorie needs based on your stats, activity level, and goal.
Result
Fill in the inputs to see your result.
Inputs
Try an example
How it works
A 500 kcal/day deficit produces roughly 0.45 kg (1 lb) of fat loss per week. Surplus works the same way for gain.
Formula
Calories = BMR × activity factor + goal adjustment
Common mistakes
- Underreporting calories from drinks, oils and snacks.
- Picking too aggressive a deficit — it backfires.
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Last updated
Reviewed Apr 15, 2026.
Calcxo gives you the answer plus the reasoning behind it.
Quick answer
Calorie Calculator: in one paragraph
Your daily calorie target is your basal metabolic rate (BMR) multiplied by an activity factor, then adjusted up or down depending on whether you want to gain, maintain, or lose weight.
What this calculator does
Using the Mifflin–St Jeor equation, the calculator estimates how many calories your body burns in a day. It then suggests targets for losing about half a kilogram (1 lb) per week, maintaining your current weight, or gaining at a similar rate.
Why people use it
- Set a realistic daily calorie target backed by a standard formula.
- Understand how activity level changes the number you should eat.
- Plan a sustainable deficit instead of guessing.
- Compare maintenance to weight-loss or weight-gain targets at a glance.
A worked calorie calculation
A concrete walkthrough you can follow line by line.
A 30-year-old woman, 165 cm, 65 kg, moderately active (exercise 3–5 days/week).
1. BMR (Mifflin–St Jeor)
10·65 + 6.25·165 − 5·30 − 161 = 1,370 kcal/day
2. Activity factor
Moderate × 1.55 → 1,370 × 1.55 ≈ 2,124 kcal/day
3. Adjust for goal
Lose 0.5 kg/week → subtract ≈ 500 kcal → ≈ 1,624 kcal/day
Result
Maintain at ≈ 2,124 kcal/day, lose at ≈ 1,624 kcal/day.
When to use this calculator
- Setting up a new diet, training plan, or food log.
- Re-checking your target after a meaningful weight or activity change.
- Avoid using the result as a strict daily quota — it's an estimate, not a prescription.
Common mistakes
- Overestimating activity level — most desk workers fall closer to 'light' than 'moderate'.
- Treating the number as exact instead of a starting point to refine over a few weeks.
- Cutting calories aggressively (more than ~25% below maintenance) and stalling progress.
- Forgetting to recalculate after losing or gaining noticeable weight.
Quick questions
Which formula does this use?+
Mifflin–St Jeor for BMR, then a Harris–Benedict-style activity multiplier. It's the most widely cited estimate for healthy adults.
How accurate is the calorie estimate?+
Within roughly ±10% for most adults. Two people with identical inputs can differ by hundreds of calories per day, so use the result as a starting point and adjust based on real-world results over 2–3 weeks.
Learn more
Deeper reads from the Calcxo learn library.
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Revision history2 changes · last on Apr 5, 2026⌄
- FormulaSwitched to Mifflin–St Jeor as the default BMR formula.Reviewed by Calcxo health desk
- ReleasedInitial release.