What maintenance calories are
They are the energy you burn over a full day, also called your total daily energy expenditure (TDEE): what your body uses at rest, what you burn moving and training, and what it costs to digest your food. If you eat that amount, your weight stays stable. It is the baseline number for any plan, and this maintenance calorie calculator is where every deficit and surplus starts.
Basal metabolic rate (BMR): what you burn without moving
Your basal metabolic rate is what your body burns at rest just to stay alive. For most people it accounts for more than half of daily expenditure. The calculator estimates it with the Mifflin-St Jeor equation, developed in 1990 with 498 healthy people aged 19 to 78:
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
In that same study, the classic Harris-Benedict equation overestimated resting expenditure by 5%. If you know your body fat percentage, the calculator uses the Cunningham (1991) equation, which is based on lean mass and tends to be more accurate for very muscular people.
The activity factor
Maintenance is calculated by multiplying your BMR by a factor based on your daily routine. These are conventional estimates: choose the level that best describes your typical week, not your best one.
| Level | Factor | Example |
|---|---|---|
| Sedentary | 1.2 | Office job and little movement |
| Light | 1.375 | Exercise 1-3 days per week |
| Moderate | 1.55 | Exercise 3-5 days per week |
| High | 1.725 | Hard training 6-7 days |
| Very high | 1.9 | Physical job plus daily training |
The most common mistake: overestimating your activity
Training for an hour four days a week does not make you "very active" if you sit for the rest of the day. When in doubt, choose the lower level and adjust later based on your actual weight. What you burn walking every day matters much more than it seems: we cover it in how many steps a day to lose weight and in how many calories you burn at the gym.
How to check that the number is right for you
No formula knows your exact metabolism: the review by Frankenfield and colleagues (2005) found that even the best equation is off by more than 10% for some people. Eat the calculated number for 2 or 3 weeks, weigh yourself several times a week under the same conditions and watch the trend: if your weight goes up, your real maintenance is somewhat lower; if it goes down, somewhat higher.
