Resting energy
What your body burns doing nothing, from the Mifflin–St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, then +5 for men or −161 for women.
Calorie deficit
calculator.
See roughly how much you burn in a day, and how much to eat to lose weight at a pace you can keep. It uses the same math as our app, Forward.
Your numbers
Fill in your details to see your numbers.
No magic
How the
numbers work.
Daily burn
Resting energy times your activity level. Forward uses 1.2 when it has no Apple Health data, and your real steps and workouts when it does.
The deficit
About 7,700 kcal ≈ 1 kg of body weight, so 0.5 kg a week is a deficit of about 550 kcal a day. Loss usually slows as you get lighter, so treat the date as a rough guide.
Safety floors
We don’t suggest eating under 1,200 kcal a day (women) or 1,500 (men), or a goal below a BMI of 18.5. If every pace is too steep, the gentle one eats at the floor.
Source: Mifflin et al., American Journal of Clinical Nutrition (1990)
Questions,
answered.
What is a calorie deficit?
Eating fewer calories than you burn. Your body makes up the difference from stored energy, which is how weight comes off. Every diet that works, whether it’s keto, fasting or counting, works because it creates one.
How big a deficit should I aim for?
For most people, 0.25–0.75 kg (0.5–1.5 lb) a week, which is about 280–830 kcal a day. Smaller deficits are easier to keep up, and keeping it up matters more than speed.
Why is my result different from other calculators?
Calculators use different formulas and activity multipliers, and all of them are estimates. Pick one, follow it for a few weeks, and adjust based on your actual weight trend.
Is this medical advice?
No. It’s a general estimate for healthy adults. If you’re under 18, pregnant or breastfeeding, have a medical condition, or have a history of disordered eating, talk to a doctor before changing how you eat.
Forward does this
every day.
Forward turns this into one number on your phone: what’s left to eat today, using your real activity from Apple Health. It’s coming to iPhone.