ReckonBoxHow this calculator works
Total daily energy expenditure is the number of calories you burn in a day, from resting metabolism through digestion to every step you take. It is the number you eat around to hold your weight, and the anchor for any plan to lose or gain. This tool finds your resting burn first, then multiplies it by how active you are.
The resting part comes from the Mifflin-St Jeor equation, the one a 2005 review rated most accurate for the general population. Enter a body fat percentage and the tool switches to Katch-McArdle, which works from lean mass instead of total weight. Multiply that resting number by an activity factor and you have your TDEE.
Take a 30 year old man, 180 cm and 75 kg, training four days a week. His resting burn is 1,730 calories. Moderate activity multiplies that by 1.55, so his TDEE is about 2,682 calories a day. Eat near that and his weight holds.
The activity multipliers
Most tools hide these numbers behind a dropdown. Here they are in full, so you can see exactly what your choice does. Pick honestly: many people rate themselves a tier too high.
| Activity level | What it means | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.2 |
| Light | Light exercise 1 to 3 days a week | 1.375 |
| Moderate | Exercise 3 to 5 days a week | 1.55 |
| Active | Hard exercise 6 to 7 days a week | 1.725 |
| Very active | Physical job or twice-daily training | 1.9 |
BMR and TDEE are not the same
Basal metabolic rate is what you burn at complete rest; TDEE is that plus everything you do. The gap between them is real energy: digesting food costs around 10 percent of your intake, and movement covers both deliberate exercise and the fidgeting, standing, and walking that researchers call NEAT. NEAT is why two people with the same BMR can burn very different totals. If you want the resting number on its own, the BMR calculator breaks it down.
Calories for your goal
Once you know your TDEE, a goal is a nudge up or down from it.
- To lose weight, eat below your TDEE. A pound of fat holds about 3,500 calories, so a 500 calorie daily deficit sheds roughly a pound a week. A gentler 250 deficit loses about half that and is easier to sustain.
- To hold weight, eat at your TDEE.
- To gain, add about 500 calories a day, lean toward strength training, and expect a mix of muscle and fat.
The tool shows all of these at once. For the protein, carbs, and fat behind the number, use the macro calculator.
How accurate is this?
Prediction equations land within about 10 percent of measured energy expenditure for most people, which is why the tool shows a likely range rather than a single confident figure. Your real number depends on genetics, muscle, and how much you move without noticing. The honest method is to eat at the estimate for two to three weeks, track your weight, and adjust by 100 to 200 calories based on what actually happens.
Special situations
Pregnancy and breastfeeding raise energy needs well beyond a standard estimate, and growing teenagers have their own requirements. This tool models healthy adults and does not adjust for those cases, so anyone in them should work from tailored guidance. It is an estimate, not medical advice. For a plan built around your health, talk to a doctor or a registered dietitian.
Frequently asked questions
What is TDEE? TDEE is your total daily energy expenditure, the calories you burn in a day from resting metabolism, digestion, and all movement. It is the number you eat around to keep your weight steady.
What is the difference between BMR and TDEE? BMR is what you burn at complete rest. TDEE is BMR multiplied by an activity factor, so it is always higher and reflects how much you move.
How many calories should I eat to lose weight? A deficit of about 500 calories a day below your TDEE loses roughly half a kilo, or one pound, a week. Smaller deficits lose weight more slowly and are easier to hold.