Macro Calculator
Pick one of two ways to split your calories. Daily target takes your age, sex, height, weight, activity level and goal. It estimates your daily calories with the Mifflin–St Jeor equation, then splits them into grams of protein, carbs and fat. Protein is set at 2.2 g per kg of body weight, fat at 25% of calories, and carbs take the rest. The goal is to maintain, lose (500 calories less) or gain (500 calories more). Ranges and keto takes your calories and shows a range in grams for each macro, from the standard adult ranges or from a typical keto split.
How to use the Macro Calculator
- Pick Daily target or Ranges and keto above the form.
- In Daily target, enter your age, sex, height, weight, activity level and goal, then press Calculate Macros.
- In Ranges and keto, choose Standard adult ranges or Keto, enter your calories and press Calculate.
- To try other numbers, change any value and press the button again.
The macro calculations
Calories = Mifflin–St Jeor BMR × activity factor ± 500 · · · Protein (g) = weight (kg) × 2.2 · · · Fat (g) = calories × 25% ÷ 9 · · · Carbs (g) = (calories − protein × 4 − fat × 9) ÷ 4 · · · Ranges and keto: grams = calories × percent ÷ 100 ÷ calories per gram
The Mifflin–St Jeor equation, published in 1990 in the American Journal of Clinical Nutrition, estimates the calories you burn at rest: 10 × weight in kg + 6.25 × height in cm − 5 × age in years, plus 5 for men or minus 161 for women. The calculator multiplies that by the activity factor, which runs from 1.2 for sedentary to 1.9 for extra active, and adds the goal. Protein and fat use fixed rates, so the split only moves when your inputs do. The calculator counts 4 calories per gram of protein and of carbs and 9 per gram of fat, the general factors US nutrition labels use under 21 CFR 101.9. If protein and fat use up every calorie, carbs show as 0. Heights and weights in feet, inches and pounds are converted at 2.54 cm per inch and 0.45359237 kg per pound, and the results are rounded to whole calories and grams. In Ranges and keto, the standard adult ranges are protein 10% to 35%, carbs 45% to 65% and fat 20% to 35% of calories, from the Dietary Guidelines for Americans 2020-2025. The keto split is fat 70% to 80%, carbs 5% to 10% and protein 10% to 20%, the shares Harvard's Nutrition Source reports from popular keto resources.
Worked example
A 35-year-old woman, 5'5" and 150 lb, lightly active, with the goal set to maintain: 1,892 calories, 150 g protein, 205 g carbs and 53 g fat. Switch the goal to lose weight and calories drop to 1,392, carbs to 111 g and fat to 39 g. Protein stays at 150 g. In Ranges and keto at 2,000 calories, the standard adult ranges are protein 50 to 175 g, carbs 225 to 325 g and fat 44 to 78 g. Keto gives protein 50 to 100 g, carbs 25 to 50 g and fat 156 to 178 g.
Frequently asked questions
What are keto macros?
There is no one standard keto ratio. Harvard's Nutrition Source says popular keto resources suggest an average of 70% to 80% of calories from fat, 5% to 10% from carbs and 10% to 20% from protein, and that the diet typically keeps carbs under 50 g a day. Its own example for 2,000 calories is about 165 g fat, 40 g carbs and 75 g protein, which sits inside the ranges this page shows. Above 2,000 calories the top of the 5% to 10% carb range passes 50 g, and the result says so.
Does keto work, and is it safe?
This page cannot promise that. Harvard's review says research is still limited, with most studies small and short. It reports short-term weight loss in some people, but results after one year were not significantly different from conventional weight loss diets. It lists suggested long-term risks such as kidney stones and osteoporosis, and it advises seeing a physician and a dietitian before you start. Ketoacidosis most often affects people with type 1 diabetes, so speak to your doctor first if you have diabetes.
Can I set my own macro ratio?
Not as a free choice. Daily target always uses 2.2 g per kg and 25% fat, and carbs get what is left. Ranges and keto shows fixed ranges. To try a split such as 30% protein, 40% carbs and 30% fat, take the calorie figure and work it out by hand. At 1,892 calories that comes to 142 g protein, 189 g carbs and 63 g fat.
Why do the standard ranges add up to more than my calories?
Each range is a limit for one macro, so the three overlap. The high ends add up to 135% and the low ends to 75%. Pick shares that add up to 100%, for example 20% protein, 50% carbs and 30% fat.
Does the goal change my protein?
Not in Daily target. Losing or gaining weight moves calories by 500, and carbs and fat absorb the change. Protein depends only on body weight, so the 150 lb woman above gets 150 g on every setting.
Is Daily target low-carb?
No. Carbs are whatever is left after protein and fat, so there is no carb limit to set. The woman above still gets 111 g of carbs on the lose setting. For a keto split, use Ranges and keto.