Calorie & macro calculator
Find out how many calories you burn in a day, how much to eat to lose fat or build muscle, and how that splits into protein, carbs and fat.
- Maintenance calories (TDEE)
- Protein, carbs and fat in grams
- Free, no sign-up
2,190kcal / day
An estimate for healthy adults, not medical advice.
How your calories and macros are calculated
- 01
Basal metabolic rate
First, the calories your body burns at complete rest, from the Mifflin–St Jeor equation — the one dietitians rely on most, because it holds up best in studies.
Men: 10 × kg + 6.25 × cm − 5 × age + 5 Women: 10 × kg + 6.25 × cm − 5 × age − 161
- 02
Maintenance calories (TDEE)
Your BMR is multiplied by an activity factor, from 1.2 for a desk job with no exercise to 1.9 for a physical job plus daily training. The result is roughly what you burn in a day: eat this much and your weight stays steady.
TDEE = BMR × activity factor (1.2–1.9)
- 03
Goal and macros
Fat loss takes 20% off maintenance; muscle gain adds 10%. Protein is set first — 2.0 g per kg of body weight for fat loss, 1.8 for muscle gain, 1.6 to maintain — then 25% of calories go to fat and the rest to carbs.
Protein, carbs: 4 kcal per g Fat: 9 kcal per g
If your BMI is above 27, protein is based on the weight that would put you at a BMI of 27, so the target stays realistic. Daily targets never go below 1,500 kcal for men or 1,200 kcal for women.
Turning the numbers into results
- 01Treat it as a starting pointAny formula can be off by around 10% for a given person. Eat at your target for two to three weeks, then let your weekly average weight tell you whether to adjust.
- 02Adjust by 100–200 kcal at a timeWeigh yourself a few mornings a week and compare weekly averages. If nothing has moved after three weeks, change your target by 100–200 kcal a day, not more.
- 03Hit your protein firstIf you only track one number, make it protein. It keeps you full, protects muscle while you're in a deficit, and it's the macro most people undereat.
Targets that come with meals
Every AI Workout plan includes nutrition: daily calories and macros set from your goal and body, separate targets for training and rest days, and days of meals built around your diet and allergies — in the same plan as your workouts.
Get my nutrition plan- Training-day and rest-day targets
- Meals around your diet and allergies
- Supplement guidance tied to your plan
Calorie and macro questions
What is TDEE?+
TDEE stands for total daily energy expenditure: everything you burn in a day, from keeping your body running at rest to digesting food, moving around and training. Eating at your TDEE keeps your weight stable; eating below it means losing weight, and above it, gaining.
How accurate is this calorie calculator?+
The Mifflin–St Jeor equation predicts resting metabolism within about 10% for most adults, and the activity factor adds more uncertainty on top. That's why the number is a starting point: track your weight for a few weeks and adjust from there.
How much protein do I need?+
Research on people who train supports roughly 1.6–2.2 g of protein per kg of body weight a day, with the higher end most useful while losing fat. This calculator uses 1.6 g to maintain, 1.8 g to build muscle and 2.0 g to lose fat.
How fast should I lose weight?+
Around 0.5–1% of your body weight a week is a sustainable pace that keeps your muscle. The 20% deficit used here puts most people in that range. Faster loss tends to cost muscle and is harder to keep up.
Should I eat back the calories I burn exercising?+
No — your activity level already accounts for your training, so adding workout calories on top would count them twice. If your training changes a lot, choose a different activity level instead.
Who shouldn't rely on this calculator?+
It's built for healthy adults. If you're pregnant or breastfeeding, under 18, managing a medical condition or have a history of disordered eating, talk to a doctor or registered dietitian before changing how you eat.
Your numbers are a start. Your plan does the rest.
AI Workout builds your training and nutrition together — calories, macros and meals that match your workouts, adjusted every week.