AI-generated imageFree tools · Updated 2026-10-22
TDEE calculator
Your TDEE (total daily energy expenditure) is about how many calories you burn in a day. This calculator estimates your resting metabolism with the Mifflin-St Jeor equation, then multiplies it by your activity level. Eat about your TDEE to hold your weight. To lose fat, eat about 10 to 20 percent less; to gain muscle, eat about 5 to 10 percent more.
2,230 calories a day to hold your weight
| Resting metabolism (Mifflin-St Jeor) | 1,440 |
| Lose fat (about 15 percent less) | 1,890 |
| Gain muscle (about 7 percent more) | 2,380 |
That fat-loss number would be below the minimum health experts advise without medical supervision. Talk to a doctor or registered dietitian before eating that little.
How it works
First it estimates your resting metabolism, the calories your body burns at rest, with the Mifflin-St Jeor equation from 1990. A review comparing the common equations found it was the most reliable for most adults. Then it multiplies by an activity factor, from 1.2 for mostly sitting to 1.9 for a physical job plus hard training.
Use it as a starting point
Everyone's real number is a bit different. Eat at your estimate for two to four weeks while you log your food and weigh yourself a few times a week. If your weekly average weight holds steady, you've found your maintenance. If it drifts, move your calories by 100 to 200 a day and check again.
Weight loss also slows over time. As you lose weight you burn fewer calories, so the old "3,500 calories per pound" rule overestimates long-term loss. That's why adjusting from your own trend works better than a fixed formula.
Keep it safe
A moderate deficit is easier to keep up and protects muscle, especially with enough protein. Health experts advise not eating below about 1,200 calories a day for women or 1,500 for men without medical supervision, so this calculator won't show a target below that. If counting food ever feels hard on your mental health, stop and talk to a professional.
Also asked
What is TDEE?
TDEE (total daily energy expenditure) is the number of calories you burn in a day, including your resting metabolism and all your movement. Eating about that many calories keeps your weight roughly steady.
How accurate is a TDEE calculator?
It is a starting estimate. The Mifflin-St Jeor equation predicted resting metabolism within 10 percent for most people in a review of the research, and activity adds more uncertainty. Track your weight for two to four weeks and adjust from what actually happens.
How many calories should I eat to lose weight?
A moderate deficit of about 10 to 20 percent below your TDEE is a sensible start for most people. Without medical supervision, health experts advise not going below about 1,200 calories a day for women or 1,500 for men.
Why does the calculator ask for sex?
The equation was built with separate versions for male and female bodies because resting metabolism differs on average. Choose the one that best fits your body, or try both and use a number in between.
Sources
- Mifflin et al. (1990), A new predictive equation for resting energy expenditure in healthy individuals
- Frankenfield et al. (2005), Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults
- Hall et al. (2011), Quantification of the effect of energy imbalance on bodyweight
- Harvard Health Publishing, Calorie counting made easy
- National Institute of Diabetes and Digestive and Kidney Diseases, Body Weight Planner