Free calculator
Calorie calculator
Your resting energy, your maintenance calories, and a gentle target for losing, keeping or gaining. Worked out in your browser; nothing is sent anywhere.
Work out your calories
Maintenance
—calories a day
- Resting energy (BMR)
- —
Enter your age, height and weight to see your numbers.
How it works
Resting energy, the calories your body uses at rest (BMR), comes from the Mifflin–St Jeor equation. Maintenance (TDEE) is that times a standard activity factor. The targets are starting points to adjust, never a promise of how your weight will change.
Resting = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (male) or − 161 (female); −78, the midpoint, if you'd rather not say
Maintenance = resting × 1.2 · 1.375 · 1.55 · 1.725 · 1.9 (mostly sitting to extremely active)
Lose = maintenance − 20 %, at most 500 · Gain = maintenance + 300
"Lose" never goes below your resting energy or a common minimum of 1,200 calories (1,500 for men). Under 18 it stays at maintenance: no deficit while you're still growing. Pregnant or breastfeeding, it stays at maintenance too. Numbers are rounded to the nearest 5.
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247. doi.org/10.1093/ajcn/51.2.241
Questions
What's the difference between BMR and maintenance calories?
BMR, or resting energy, is what your body burns at rest. Maintenance, often called TDEE, adds your daily movement and training on top: resting energy times an activity factor from 1.2 to 1.9.
How accurate is this?
It's an estimate. The Mifflin–St Jeor equation is a common choice for healthy adults, but real needs vary from person to person. Use the number as a starting point and adjust it by how you feel and how your weight trends over a few weeks.
Why won't the "lose" number go lower?
Fullday keeps any deficit gentle: 20 % under maintenance at most, never more than 500 calories, and never below your resting energy or 1,200 calories (1,500 for men).
Can teenagers or pregnant women use it?
Under 18, and while pregnant or breastfeeding, "lose" stays at maintenance, as it does in the app. Growing bodies and pregnancy have their own needs, so talk to a doctor, midwife or registered dietitian before changing how much you eat. The same goes for anyone with a medical condition or a history of disordered eating.
Fullday tracks this for you every day.
It suggests starting targets by this same rule, which you can accept or change, and counts the food you log against them. Coming to the App Store this December, free to download.
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