How the numbers work
No black box. Here is every rule the calculator follows, and a worked example you can check by hand.
Calories
Maintenance, the calories that hold your weight steady, is your bodyweight in pounds × 12.
Kilograms become pounds at 2.2, the worksheet's round figure, for this sum only. A weight you log is converted at the exact pound.
Your daily target starts from your goal bodyweight in pounds × 12. A lighter goal gives a deficit (a cut), a heavier goal a surplus (a build). The gap is widest at the start and narrows as your weight nears the goal.
A sustainable pace
A cut is held to a sustainable pace: the deficit never asks for more than 0.75% of your bodyweight a week, counting 7,700 kcal in a kilogram of body fat.
With no change of weight to aim for, a cut or a build moves by that same step: 0.75% of bodyweight a week, below or above maintenance.
Macros
The calories are shared out as 37% protein, 25% fat, 35% carbs and 3% fibre. Fibre is part of carbs but gets its own line, so it is not forgotten.
Each share becomes grams at 4 kcal a gram for protein and carbs, 9 for fat and 2 for fibre.
Meals
A day divides evenly between its meals. With an afternoon snack, the snack takes 15% of the day and the meals share the rest. A meal's calories are rounded to the nearest 5.
Food
A food's weight is not its macro weight. The calculator works from what 100 g of each food carries: 100 g of chicken breast is 31 g of protein, not 100 g. To hit a target it divides: grams of protein wanted ÷ 31 × 100 = grams of chicken breast.
In the Pacer app
In the Pacer app, your daily calorie and macro targets follow this method whenever a goal weight is set, with one addition for anyone on a GLP-1 medicine: a higher protein floor, made up from carbs and then fat, so the calories do not change. Without a goal weight, the app estimates maintenance from your BMR and activity level instead.
The app adds one rail this calculator cannot know: a cut never goes below your BMR (from your profile or a recent body scan), and never above maintenance.
A worked example
A sample person, 105 kg today and aiming for 85 kg. Every figure below is the calculator's own.
- Maintenance
- 2,772 kcal
- Daily target
- 2,244 kcal
- Protein
- 208 g
- Pounds. 105 kg × 2.2 = 231 lb today, and 85 kg × 2.2 = 187 lb at the goal.
- Maintenance. 231 lb × 12 = 2,772 kcal a day.
- Goal. 187 lb × 12 = 2,244 kcal a day, a gap of 528 kcal.
- Pace check. 105 kg × 0.75% × 7,700 kcal ÷ 7 days = 866 kcal a day, the most a cut may ask for. The gap is inside that, so the target stays 2,244 kcal.
- To start. 528 kcal × 7 days ÷ 7,700 kcal = about 0.48 kg a week.
- Macros.
- Protein: 37% × 2,244 kcal ÷ 4 = 208 g
- Fat: 25% × 2,244 kcal ÷ 9 = 62 g
- Carbs: 35% × 2,244 kcal ÷ 4 = 196 g
- Fibre: 3% × 2,244 kcal ÷ 2 = 34 g
- Meals.
- 2 meals: each meal 1,120 kcal, 104 g protein, 31 g fat, 98 g carbs.
- 3 meals: each meal 750 kcal, 69 g protein, 21 g fat, 65 g carbs.
- 2 meals and a snack: each meal 955 kcal, 88 g protein, 26 g fat, 83 g carbs; the snack 335 kcal, 31 g protein, 9 g fat, 29 g carbs.
- 3 meals and a snack: each meal 635 kcal, 59 g protein, 18 g fat, 56 g carbs; the snack 335 kcal, 31 g protein, 9 g fat, 29 g carbs.
- Food. With 2 meals, one meal's 104 g of protein ÷ 31 × 100 is about 335 g of chicken breast.
The same method everywhere
Pacer on iPhone and the web app work these out the same way. Maintenance, the pace cap and the macro split are checked against one shared set of worked examples in both apps' tests.
The calculator on this site runs on the web app's own engine, read in place rather than copied.
General guidance, not medical or dietary advice. Values are approximate and shift with brand, cut and cooking. If you have a medical condition, check with a clinician.