How the numbers are worked out
- Resting calories (BMR). Your age, sex, height and weight give an estimate of what your body burns at complete rest (the Mifflin-St Jeor equation). This is your basal metabolic rate, or BMR.
- Maintenance calories (TDEE). Your BMR is multiplied by your activity level, from 1.2 if you mostly sit to 1.9 for a physical job and hard training, to estimate the calories that keep your weight steady. This is your total daily energy expenditure, or TDEE.
- Your goal. For fat loss, calories are set to lose about 0.5% of your body weight a week, a pace that protects muscle. For building muscle, they are set about 7.5% above maintenance, which keeps fat gain low.
- Macros. Protein is 2.2 g per kg of body weight for fat loss and 1.8 g per kg otherwise. Fat is a quarter of your calories. Carbohydrate makes up the rest, to fuel your training.
The reasons behind each number are explained in how much protein you need, how to lose fat without losing muscle and how fast to gain weight on a lean bulk.
What to do with your numbers
Follow the targets for two to three weeks, weighing yourself each morning, and compare your weekly average weight with your goal. If it is moving too fast or too slowly, adjust by 100 to 200 calories a day and give it another two weeks. Our guide to reading the scale explains why daily weight is not a reliable signal on its own.
Calculators are a start. Coaching is the part where someone reads your results every week and changes the plan when the numbers say so. If you want that, apply for coaching with CoachAk.
Common questions
How accurate is a macro calculator?
It gives a sensible starting estimate, usually within a few hundred calories of your real maintenance. The only way to know for sure is to follow the targets for two to three weeks, track your weekly average weight, and adjust.
Which formula does this calculator use?
It estimates your resting energy use with the Mifflin-St Jeor equation, then multiplies it by an activity factor based on your daily steps and training.
Is this a TDEE calculator?
Yes. Your maintenance calories are your TDEE (total daily energy expenditure): your resting calories, or BMR (basal metabolic rate), multiplied by an activity factor. The calculator shows both, then sets your daily target for fat loss, maintenance or muscle gain from your TDEE.
Why is protein higher when losing fat?
Eating less makes your body more willing to break down muscle for energy. Higher protein, along with heavy training, helps you keep it. The calculator uses 2.2 g per kg of body weight for fat loss and 1.8 g per kg otherwise.
I have a lot of weight to lose. Should I use my current weight?
For protein, use your goal weight rather than your current weight, otherwise the protein target comes out higher than you need.
This calculator gives general estimates for healthy adults and is not medical advice. If you have a medical condition, are pregnant or have a history of disordered eating, speak to your doctor before changing your diet.