Calorie calculator
Find out how many calories you burn in a day, and what a sensible target looks like if you want to lose or gain. Same formula and same safety limits as the Kalorea app.
- Resting burn (BMR)
- 1,379 kcal
- Lose gently1,870 kcal
- Lose steadily1,737 kcal
- Lose at the safe maximum1,603 kcal
- Keep your weight2,137 kcal
- Gain2,458 kcal
We don't suggest a calorie deficit under 18 or with a BMI below 18.5. Talk to a doctor about your goals.
What the numbers mean
Resting burn (BMR) is what your body spends doing nothing at all: breathing, keeping warm, running your organs. It's usually 60 to 70% of what you burn in a day.
Maintenance adds everything else: walking around, work, training. Eat this much and your weight stays roughly where it is. It's the number most people mean when they ask how many calories they should eat a day.
Targets are maintenance minus a deficit to lose weight, or plus a surplus to gain. We never go below your resting burn, and we cap the pace at 1% of body weight a week.
How to use it in real life
Pick a target and live with it for two to three weeks before judging it. Daily weight jumps by a kilo or more from water and salt alone; the weekly average is what tells the truth.
If the average doesn't move after three weeks, the problem is usually counting, not the formula: oil, drinks and snacks are where calories hide. That is exactly what photo logging with a range helps you see.
Maintenance calories by age and activity
Calories a day to keep your weight, from the same formula. Women: 165 cm (5 ft 5 in), 65 kg (143 lb). Men: 178 cm (5 ft 10 in), 80 kg (176 lb). Your own number depends on your height and weight, so use the calculator above for it.
Women
| Age | Sitting | Walking | Train 2-3× | Train daily |
|---|---|---|---|---|
| 20 | 1,704 | 1,953 | 2,201 | 2,450 |
| 25 | 1,674 | 1,918 | 2,163 | 2,407 |
| 30 | 1,644 | 1,884 | 2,124 | 2,364 |
| 35 | 1,614 | 1,850 | 2,085 | 2,321 |
| 40 | 1,584 | 1,815 | 2,046 | 2,277 |
| 45 | 1,554 | 1,781 | 2,008 | 2,234 |
| 50 | 1,524 | 1,747 | 1,969 | 2,191 |
| 55 | 1,494 | 1,712 | 1,930 | 2,148 |
| 60 | 1,464 | 1,678 | 1,891 | 2,105 |
| 65 | 1,434 | 1,643 | 1,853 | 2,062 |
| 70 | 1,404 | 1,609 | 1,814 | 2,019 |
Men
| Age | Sitting | Walking | Train 2-3× | Train daily |
|---|---|---|---|---|
| 20 | 2,181 | 2,499 | 2,817 | 3,135 |
| 25 | 2,151 | 2,465 | 2,778 | 3,092 |
| 30 | 2,121 | 2,430 | 2,740 | 3,049 |
| 35 | 2,091 | 2,396 | 2,701 | 3,006 |
| 40 | 2,061 | 2,362 | 2,662 | 2,963 |
| 45 | 2,031 | 2,327 | 2,623 | 2,920 |
| 50 | 2,001 | 2,293 | 2,585 | 2,876 |
| 55 | 1,971 | 2,258 | 2,546 | 2,833 |
| 60 | 1,941 | 2,224 | 2,507 | 2,790 |
| 65 | 1,911 | 2,190 | 2,468 | 2,747 |
| 70 | 1,881 | 2,155 | 2,430 | 2,704 |
How it's calculated
Resting burn uses the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women.
Maintenance is resting burn times an activity factor: 1.2 mostly sitting, 1.375 walking but no sport, 1.55 training 2 to 3 times a week, 1.725 training almost every day.
The deficit is capped by the strictest of three limits: 25% of maintenance, the gap between maintenance and resting burn, and a pace of 1% of body weight per week (1 kg of fat is counted as 7,700 kcal). “Gently” is half of that cap, “steadily” three quarters.
A surplus for gaining weight is 15% of maintenance.
Example: a 30-year-old woman, 168 cm, 64 kg, training 2 to 3 times a week. Resting burn is 10 × 64 + 6.25 × 168 − 5 × 30 − 161 = 1,379 kcal. Maintenance is 1,379 × 1.55 = 2,137 kcal.
Questions
Why Mifflin-St Jeor?
In studies comparing the common equations, Mifflin-St Jeor most often lands closest to measured resting burn in healthy adults. It's still an estimate: real burn varies from person to person by about 10%.
Why is there a cap on the deficit?
Eating far below your needs is hard to sustain, and losing faster than about 1% of body weight a week tends to cost muscle, not just fat. The cap keeps the plan realistic.
Should I eat back the calories from exercise?
The activity level already counts your regular training. Pick the level that matches a normal week rather than adding workouts on top.
Let the app keep score
Kalorea sets your target with this formula and then counts every meal from a photo, so you can see each day where you stand.