Calorie Calculator
See how many calories you need each day for your goal, from fat loss to muscle gain.
Your details
| Lose 1 kg / 2 lb per week | 1,633 kcal |
| Lose 0.5 kg / 1 lb per week | 2,133 kcal |
| Mild loss | 2,383 kcal |
| Maintain | 2,633 kcal |
| Mild gain | 2,883 kcal |
| Gain 0.5 kg / 1 lb per week | 3,133 kcal |
Calories are the unit of energy in food, and knowing how many you need is the foundation of every weight goal. Whether you want to lose fat, hold steady, or build muscle, it all starts from one number: the calories your body uses in a day.
How many calories do you need?
Your daily need is the total energy your body burns keeping you alive and moving. Eat that amount and your weight stays stable. Eat consistently less and you lose weight, eat more and you gain. This balance, energy in versus energy out, is the principle behind every diet that works.
How it is calculated
We first estimate your Basal Metabolic Rate, the calories you burn at rest, using the Mifflin-St Jeor equation, which is well validated for the general population. We then multiply that by an activity factor to reflect how much you move, giving your total daily calories. From there, we build targets for each goal.
Calorie targets by goal
One pound of fat holds roughly 3,500 calories, and a kilogram about 7,700, which is where the classic targets come from:
- Fat loss: about 500 calories below maintenance for roughly 0.5 kg or 1 lb lost per week.
- Maintenance: eat at your total daily calories.
- Muscle gain: 250 to 500 calories above maintenance, paired with strength training.
Quality still counts
Calories decide your weight, but the foods behind them decide how you feel and perform. Protein keeps you full and protects muscle, fiber steadies your appetite, and whole foods deliver the vitamins and minerals a healthy body needs. Two diets with the same calories can produce very different results.
Hitting the number is the hard part
Knowing your calories is easy. Actually eating them, day after day, is where people slip. SmaartCoach turns your target into a weekly meal plan with the right portions, and lets you scan your food with your camera to stay on track without hand counting every bite.
Frequently asked questions
How many calories should I eat to lose weight?
Most people lose steadily at about 500 calories below their maintenance level, which is roughly half a kilogram or one pound per week. Larger deficits work faster but are harder to sustain and can cost muscle.
How many calories to gain muscle?
A small surplus of 250 to 500 calories above maintenance, combined with strength training and enough protein, supports lean gains without excess fat.
Are calorie calculators accurate?
They give a solid estimate from proven equations, but individual needs vary. Use the number for two weeks, then adjust based on how your weight actually changes.
Should I eat back exercise calories?
Most calculators already fold activity into your total, so eating extra on top can erase your deficit. Trust the daily target and adjust with real results.
Sources
Reviewed against these authoritative references. Last updated August 2026.
- MedlinePlus, U.S. National Library of Medicine. Metabolism
- U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans
- MedlinePlus, U.S. National Library of Medicine. Body mass index
Turn these numbers into a real plan
Max builds your meals and workouts around your goal, then coaches you through it. Start free.
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