Keto Calculator — Macros, Calories & Net Carbs
Calculate your daily keto macros — fat, protein, and carb grams — from your BMR, TDEE, and goal, plus a net carbs helper for reading food labels.
BMR uses the Mifflin-St Jeor equation (Male: 10×kg + 6.25×cm − 5×age + 5; Female: 10×kg + 6.25×cm − 5×age − 161), multiplied by an activity factor to estimate TDEE, then adjusted by your goal. Macros split that calorie target using 9 kcal/g for fat and 4 kcal/g for protein and carbs. Net carbs = Total Carbs − Fiber − Sugar Alcohols (erythritol is commonly subtracted in full since it has minimal glycemic impact; other sugar alcohols are typically subtracted at half value). This tool provides general estimates, not medical advice — people with diabetes, kidney conditions, or anyone on blood-sugar or blood-pressure medication should consult a doctor before starting a ketogenic diet.
Reference Values
Last verified:| Category | Range | What It Means | Status |
|---|---|---|---|
| Standard Keto Ratio ★ | 70% fat / 25% protein / 5% carbs | The most common ketogenic macro split, designed to keep the body in nutritional ketosis for most healthy adults. | ★ Best |
| Higher-Protein Keto | ~60% fat / 35% protein / 5% carbs | A custom variant some people use to preserve muscle during a cut, at some risk of reduced ketone production if protein is very high relative to activity level. | Good |
| Fat (energy per gram) | 9 kcal/g | Fat has more than double the caloric density of protein or carbs, which is why keto's high fat percentage still yields a normal-sized calorie total. | Good |
| Protein (energy per gram) | 4 kcal/g | Standard Atwater factor used to convert protein grams to calories. | Good |
| Carbohydrate (energy per gram) | 4 kcal/g | Standard Atwater factor used to convert total and net carb grams to calories. | Good |
| Typical Net Carb Target ★ | 20-50 g/day | The commonly cited range for staying in nutritional ketosis. Individual tolerance varies — some people need to stay near the low end, others tolerate more. | ★ Best |
| Erythritol Subtraction Convention | Subtract in full | Erythritol has a negligible glycemic and insulin impact for most people, so it is commonly subtracted from total carbs in full rather than at the standard half-value used for other sugar alcohols. | Good |
| Other Sugar Alcohols (e.g. maltitol, xylitol) | Subtract at half value | Most sugar alcohols other than erythritol have a partial glycemic impact, so common practice is to subtract only half their gram weight when calculating net carbs. | Okay |
Source: Macro ratio and net-carb subtraction conventions aggregated from Harvard T.H. Chan School of Public Health, The Nutrition Source (hsph.harvard.edu/nutritionsource) and UCLA Health patient education materials on ketogenic diets and net carb counting. Individual macro needs vary — this reflects the most common general convention, not a personalized medical recommendation.
Worked Examples
Sedentary Male, Mild Weight Loss
- Sex
- Male
- Age
- 35
- Weight
- 180 lb
- Height
- 5'10"
- Activity
- Light (1-3 days/week)
- Goal
- Mild deficit (-250 kcal)
BMR ≈1,780 kcal × 1.375 activity = 2,447 kcal TDEE, minus 250 kcal goal adjustment ≈2,197 kcal. Split 70/25/5: fat 2,197×0.70÷9≈171g, protein 2,197×0.25÷4≈137g, carbs 2,197×0.05÷4≈27g (rounded).
Active Female, Weight Maintenance
- Sex
- Female
- Age
- 29
- Weight
- 140 lb
- Height
- 5'5"
- Activity
- Moderate (3-5 days/week)
- Goal
- Maintain weight
BMR ≈1,349 kcal × 1.55 activity ≈2,091 kcal TDEE, no adjustment for maintenance. Split 70/25/5: fat 2,091×0.70÷9≈163g, protein 2,091×0.25÷4≈131g, carbs 2,091×0.05÷4≈26g.
Custom Higher-Protein Split for a Lifter
- Sex
- Male
- Age
- 27
- Weight
- 200 lb
- Height
- 6'0"
- Activity
- Active (6-7 days/week)
- Goal
- Mild deficit
- Ratio
- 60% fat / 35% protein / 5% carbs
TDEE ≈2,900 kcal minus 250 kcal goal adjustment ≈2,650 kcal. Custom 60/35/5 split: fat 2,650×0.60÷9≈177g, protein 2,650×0.35÷4≈232g, carbs 2,650×0.05÷4≈33g.
Net Carbs From a Nutrition Label (Non-Erythritol Sweetener)
- Total Carbs
- 18g
- Fiber
- 6g
- Sugar Alcohols (maltitol)
- 8g
- Erythritol
- No
18 − 6 − (0.5×8) = 18 − 6 − 4 = 8g net carbs, since non-erythritol sugar alcohols are subtracted at half value.
Net Carbs From an Erythritol-Sweetened Snack
- Total Carbs
- 20g
- Fiber
- 3g
- Sugar Alcohols (erythritol)
- 12g
- Erythritol
- Yes
20 − 3 − 12 = 5g net carbs, since erythritol is subtracted in full due to its negligible glycemic impact for most people.
How to Use This Calculator
- 1
Enter your body stats
Sex, age, height, and weight, in either imperial (lb/ft-in) or metric (kg/cm) units.
- 2
Choose your activity level and goal
Activity level ranges from sedentary to very active; goal ranges from maintaining weight to a 500 kcal/day deficit or a mild surplus.
- 3
Pick a macro ratio
Use the Standard 70/25/5 keto ratio, or switch to Custom to set your own fat/protein/carb percentages (must total 100%).
- 4
Read your calorie target and macro grams
Results show your daily calorie target plus fat, protein, and carb grams needed to hit that keto ratio.
- 5
Use the net carbs helper for packaged food
Enter total carbs, fiber, and sugar alcohols from a nutrition label to get the net carb count that actually counts toward your daily carb budget.
What Each Value Means
- BMR (Basal Metabolic Rate) (kcal/day)
- The estimated number of calories your body burns at complete rest just to maintain basic functions like breathing and circulation, calculated here using the Mifflin-St Jeor equation.
- TDEE (Total Daily Energy Expenditure) (kcal/day)
- Your BMR multiplied by an activity factor, estimating total calories burned in an average day including movement and exercise.
- Net Carbs (grams)
- Total carbohydrate grams minus fiber and (partially or fully) minus sugar alcohols — the carb count that actually affects blood sugar and counts toward a keto carb budget.