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Your calories and macros,
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Enter your details and the result appears below, instantly. The math is done on your phone: nothing is stored, there’s no sign-up, and it’s exactly the same math as our diet app.
Your basal metabolic rate is about 1,674 kcal and you burn around 2,394 kcal a day including your workouts.
Where this number comes from
So you can redo the math yourself, which is the only way to trust it.
- Your basal metabolic rate. What you’d burn lying down all day. It comes from the Mifflin-St Jeor equation: ten times your weight in kilos, plus 6.25 times your height in centimeters, minus five times your age, and plus five for men or minus 161 for women.
- What you really burn. That basal rate multiplied by a factor based on the days you train, from 1.2 if you don’t train to 1.73 if you train every day. That’s your maintenance: the calories that keep you where you are.
- The goal. For a cut, 20% below maintenance, or 30% if you choose the aggressive pace. For a bulk, no percentage is used: it starts from a reasonable rate of gain —between 0.25% and 0.5% of your body weight per week— and the surplus comes from that, which is the opposite of how almost everyone does it, and the right way.
- The split. Protein, the grams per kilo (or per pound) you choose —unless they ask for more than your lean mass supports; then it’s adjusted to it and we tell you above (why). Fat, 30% of the calories, and never below 15%. Carbs, whatever is left, with a floor of 50 grams so you don’t get impossible splits.
What a number like this CAN’T know
This is an estimate, and it’s worth saying clearly: the formula was measured on 498 people and explains about 71% of the variation between them. Two people with the same weight, height, age and sex can burn different amounts, and the formula doesn’t know that. Use it as a starting point, eat that way for two or three weeks, and then correct it with what the scale says: that’s your own data, and the formula’s isn’t.
Frequently asked questions
Which formula does this calculator use?
The Mifflin-St Jeor equation for basal metabolic rate, published in the American Journal of Clinical Nutrition in 1990, and an activity factor based on the days you train per week. It's the one the Academy of Nutrition and Dietetics recommends as the most reliable of the formula-based estimates.
Why doesn't the number match another calculator's?
Because many use Harris-Benedict, which dates from 1919 and tends to overestimate, or different activity factors. None of them is spot on: the formula explains about 71% of the variation between people, so take it as a starting point and adjust it with what the scale says after two or three weeks.
How much protein should I enter?
Between 1.6 and 2.2 grams per kilo of body weight a day (about 0.7 to 1.0 g per pound) is what most of the research supports for people who do strength training. Above that, no extra muscle has been seen, and in a steep deficit high protein helps you keep what you already have. If you carry a lot of body fat, the calculator adjusts the result to your lean mass: protein is used by muscle, not by fat, so multiplying by your whole body weight asks for quite a bit more than you need.
Why does it stop my calories at a number and not go lower?
Because there's a safety minimum, 1,500 kcal for men and 1,200 for women, and it won't tell you to eat below that. If your deficit fell lower, the calculator says so instead of showing you a number you shouldn't follow.
Do you keep my data?
No. The math is done entirely in your browser: nothing is sent to any server, you don't need to sign up and we don't ask for your email to show you the result.
And now, the hard part: sticking to it
Knowing your macros is the easy bit. The other part is hitting them every day. The Reverfit Diet app does this same math, shows it to you in four rings and lets you log what you eat by scanning the barcode on the package. It’s free to start.
Diet
