# What are my keto macros?

Works out daily keto macros: a fixed number of grams of carbs, a share of protein and the rest as fat, from typed calories or from your BMR, activity and goal, checked against ketogenic diet ranges.

- Page: https://www.acalculator.org/health/keto-calculator
- JSON spec: https://www.acalculator.org/health/keto-calculator.json
- Version: 3e4750a310f1

## Default answer

Example with the default inputs (Daily calories Work them out, Sex Female, Age 30, Height 5 ft 5 in, Weight 150 lb, Activity Light: exercise 1 to 3 days, Goal Keep my weight, Carbs (g a day) 25, Protein 35%, BMR formula Mifflin-St Jeor): At 1,927 calories a day, eat about 128 g of fat, 169 g of protein and 25 g of carbs.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| known | Daily calories | Whether to work out your daily calories from your body and goal, or type them in. |
| calories | Calories a day | The calories you plan to eat each day. |
| sex | Sex | Sex at birth, which the body formulas use. |
| age | Age | Your age in whole years. |
| height | Height | Your height without shoes. |
| weight | Weight | Your body weight. |
| activity | Activity | How active you are in a usual week, which sets the multiplier on your BMR. |
| goal | Goal | Keep or lose weight, which takes from your daily calories. |
| carbs | Carbs (g a day) | Grams of carbohydrate a day; a ketogenic diet usually keeps this at 20 to 50 g. |
| protein | Protein | The share of calories from protein; about 30% to 35% on a ketogenic diet. Fat gets the rest. |
| formula | BMR formula | The equation for basal metabolic rate: Mifflin-St Jeor (1990) or the revised Harris-Benedict (1984). |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| fat | Fat a day | Grams of fat a day: the calories carbs and protein leave, ÷ 9. |
| protein | Protein a day | Grams of protein a day: calories × protein share ÷ 4. |
| carbs | Carbs a day | Grams of carbohydrate a day, as typed. |
| calories | Calories a day | The daily calories the grams are worked out from. |
| fatShare | Fat share | The share of calories from fat. |
| proteinShare | Protein share | The share of calories from protein, as typed. |
| carbsShare | Carbs share | The share of calories from carbs: carbs × 4 ÷ calories. |
| fatKcal | Calories from fat | Fat grams × 9. |
| proteinKcal | Calories from protein | Protein grams × 4. |
| carbsKcal | Calories from carbs | Carb grams × 4. |
| ranges | Against keto ranges | Whether carbs are 20 to 50 g a day and each share is in the usual keto range: fat 55–60%, protein 30–35%, carbs 5–10%. |
| limit | Note | A warning when the calories fall below the lowest intake the weight-loss guideline suggests. |

## Method

Carbs (g) as typed; protein (g) = calories × protein share ÷ 4; fat (g) = (calories − carbs × 4 − protein calories) ÷ 9. Calories are typed, or TDEE (BMR × activity factor) − the goal.

## Assumptions

- Protein and carbohydrate give 4 calories per gram and fat gives 9 (21 CFR 101.9).
- The keto ranges are from StatPearls: 20 to 50 g of carbohydrate a day; about 55–60% of calories from fat, 30–35% from protein and 5–10% from carbohydrate.
- Worked-out calories use Mifflin-St Jeor or the revised Harris-Benedict, the activity factors 1.2 to 1.9, and 500 calories a day per pound a week.
- This is an estimate for planning, not medical advice; talk to a doctor before a ketogenic diet, especially with diabetes, kidney disease or pregnancy.

## Worked examples

1. known = body, sex = female, age = 30, height = 1.651, weight = 68.038856, activity = light, goal = maintain, carbs = 25, protein = 35, formula = mifflin gives calories = 1,926.737388, fat = 0.128042, protein = 0.16859, fatShare = 59.809879%, ranges = All inside the usual keto ranges.. Source: Masood W, Annamaraju P, Khan Suheb MZ, Uppaluri KR. Ketogenic Diet. StatPearls, 2023 (https://www.ncbi.nlm.nih.gov/books/NBK499830/, retrieved 2026-10-01); Mifflin et al. 1990; 4, 4 and 9 calories per gram (21 CFR 101.9).
2. known = body, sex = male, age = 35, height = 1.778, weight = 81.646627, activity = moderate, goal = lose1, carbs = 30, protein = 30, formula = mifflin gives calories = 2,224.460212, fat = 0.15968, protein = 0.166835. Source: Mifflin et al. 1990; 500 calories a day for 1 lb a week (Wishnofsky 1958).
3. known = calories, calories = 2,000, carbs = 20, protein = 30 gives fat = 0.146667, protein = 0.15, carbsShare = 4%, ranges = Fat 66% is over the 55% to 60% range. Carbs 4% is under the 5% to 10% range.. Source: Masood W et al. Ketogenic Diet, StatPearls 2023 (fat 55–60%, protein 30–35%, carbs 5–10%, carbs 20–50 g a day).

## FAQ

### How many carbs can I eat on keto?

A ketogenic diet usually keeps carbohydrate to 20 to 50 g a day, about 5% to 10% of the calories in a 2,000-calorie diet (StatPearls). The calculator starts at 25 g; set your own number.

### What are the keto macro percentages?

StatPearls gives a typical split of about 55% to 60% of calories from fat, 30% to 35% from protein and 5% to 10% from carbohydrate. The calculator checks your split against these ranges.

### How does the keto calculator work out my grams?

Carbs are the grams you type. Protein is your calories × the protein share ÷ 4. Fat is whatever calories are left, ÷ 9. At 2,000 calories with 20 g of carbs and 30% protein: carbs give 80 calories, protein 600 calories (150 g), and fat the other 1,320 calories (146.7 g).

### How are my calories worked out?

From your basal metabolic rate (Mifflin-St Jeor, or the revised Harris-Benedict) times an activity factor from 1.2 to 1.9, less 250 calories a day for each 0.5 lb a week you want to lose.

### Should I count total or net carbs?

The calculator counts the carbohydrate grams you type and does not subtract fibre. If you track net carbs (total carbohydrate less fibre), type that number, and keep in mind the 20 to 50 g range was given for carbohydrate.

### Is a keto diet safe for everyone?

No. Talk to a doctor first, especially with diabetes medicines, kidney or liver disease, a history of eating disorders, or during pregnancy. The calculator is an estimate for planning, not medical advice.

## Sources

- Masood W, Annamaraju P, Khan Suheb MZ, Uppaluri KR. Ketogenic Diet. In: StatPearls. StatPearls Publishing; 2023 (carbohydrate 20 to 50 g a day; about 55% to 60% fat, 30% to 35% protein and 5% to 10% carbohydrate). https://www.ncbi.nlm.nih.gov/books/NBK499830/ (retrieved 2026-10-01)
- U.S. Code of Federal Regulations, 21 CFR 101.9(c)(1)(i)(C): general factors of 4, 4 and 9 calories per gram for protein, total carbohydrate and total fat. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. https://doi.org/10.1093/ajcn/51.2.241
- Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. Am J Clin Nutr. 1984;40(1):168-182. https://doi.org/10.1093/ajcn/40.1.168
- Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958;6(5):542-546. https://doi.org/10.1093/ajcn/6.5.542
- Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults. Circulation. 2014;129(25 Suppl 2):S102-S138 (lowest diets of 1,200 and 1,500 calories a day). https://pmc.ncbi.nlm.nih.gov/articles/PMC5819889/