Keto Calculator – Keto Macros
Enter your sex, age, height, weight, body fat, activity level and goal to get your personal keto macros: daily calories plus net carb, protein and fat targets in grams, per day and per meal.
Get Your Personal Keto Macro Targets
Keto Macros Formula
Where:
- \(W\) — body weight in kg, \(H\) — height in cm, \(A\) — age in years, \(s\) — +5 for men, −161 for women
- \(BF\) — body fat percentage, \(LBM\) — lean body mass in kg
- \(BMR\) — basal metabolic rate: Katch–McArdle (first equation) when body fat is known, otherwise Mifflin–St Jeor (second equation)
- \(AF\) — activity factor (1.2–1.9), \(d\) — calorie deficit or surplus in %
- \(T\) — daily calorie target, \(C\) — net carbs in g, \(P\) — protein in g, \(r\) — protein per kg of lean mass, \(F\) — fat in g
On keto, carbs and protein are set first: carbs stay below the limit that keeps you in ketosis, and protein is set from your lean mass. Fat then fills all the remaining calories, because it is the only adjustable macro.
Keto Macros – Calculation Example
Example: a 35-year-old woman, 165 cm tall, weighing 70 kg with 25% body fat, lightly active (1.375), aiming to lose fat with a 20% deficit, 20 g net carbs and 1.6 g protein per kg of lean mass.
\[ LBM = 70 \times (1 - 0.25) = 52.5 \text{ kg}, \quad BMR = 370 + 21.6 \times 52.5 = 1504 \text{ kcal} \]
\[ TDEE = 1504 \times 1.375 = 2068 \text{ kcal}, \quad T = 2068 \times 0.8 = 1654 \text{ kcal} \]
\[ P = 1.6 \times 52.5 = 84 \text{ g}, \quad F = \frac{1654 - 20\times4 - 84\times4}{9} = \frac{1238}{9} \approx 138 \text{ g} \]
Result: about 1654 kcal per day: 20 g net carbs (5% of calories), 84 g protein (20%), and 138 g fat (75%), or per meal across 3 meals: ~7 g carbs, 28 g protein and 46 g fat.
How to use the calculator
- Choose your Sex and enter your Age — both feed the BMR estimate.
- Pick a Height format (centimeters or feet and inches) and enter your Height and Weight; you can switch the weight unit between kg and lb.
- If you know your body fat percentage (from a DEXA scan, a BIA scale or calipers), tick Use body fat % (more accurate BMR) and enter it. The calculator then switches to the Katch–McArdle formula; otherwise body fat is estimated from your BMI, age and sex.
- Select your Activity level — the factor should reflect a typical week, not your best week.
- Choose a Goal: lose fat, maintain weight, or gain weight. For fat loss, set the Calorie deficit (15–20% is a sustainable pace); for gaining, set the Calorie surplus.
- Adjust the keto targets if needed: Net carb limit (20–25 g keeps most people in ketosis) and Protein per kg of lean mass (1.6 g/kg is typical on keto).
- Choose Meals per day to get a per-meal breakdown, then read your results: daily calorie target with BMR and TDEE, a macro table in grams and % of calories, a macro split chart, and the per-meal amounts.
What keto macros are and how to read the result
A ketogenic diet works by keeping net carbohydrates (total carbs minus fiber) low enough that your body runs out of glucose and switches to burning fat and ketones. For most people that means 20–25 g of net carbs per day, which is why carbs are capped first in the calculation, not adjusted to fit a calorie target.
Protein is set second. It has to be high enough to protect your muscle mass — especially in a calorie deficit, where eating too little protein means losing muscle along with fat — but not so high that it crowds out fat. That is why the target is based on lean body mass rather than total weight: two people who weigh the same but have different body fat percentages need different protein amounts.
Fat is the flexible macro. After carbs and protein are fixed, fat simply supplies whatever calories remain to hit your daily target. This is why fat grams change the most when you adjust the deficit or surplus: on keto, fat is your energy dial. If the calculator shows fat below roughly 60% of calories, the combination may no longer be reliably ketogenic.
The result is a starting point, not a verdict. Track your weight and how you feel over 2–4 weeks; if fat loss stalls, a slightly larger deficit or more activity usually works better than cutting protein. To check whether the deficit is producing results, try the weight loss percentage calculator.
Activity factor reference
| Activity level | Factor | Typical day |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Lightly active | 1.375 | Light exercise 1–3 days/week |
| Moderately active | 1.55 | Moderate exercise 3–5 days/week |
| Very active | 1.725 | Hard exercise 6–7 days/week |
| Extra active | 1.9 | Physical job plus hard daily training |
Assumptions and limitations
- BMR equations are estimates — real maintenance calories can differ by 10–20% even with perfect inputs. People vary.
- If you do not enter body fat, it is estimated from BMI, age and sex (the Deurenberg formula). This is rough and less accurate for muscular or older adults; a measured reading is always better. For a measured body fat goal, the Army body fat calculator estimates it from tape measurements.
- Gym BIA scales and even calipers can be off by several percentage points; a 3% error in body fat shifts both the protein target and the Katch–McArdle BMR.
- The per-meal breakdown assumes equally sized meals. On keto this is optional — total daily macros matter most, though keeping each meal under about 10–15 g of net carbs helps some people stay in ketosis.
- Macro ratios alone do not guarantee ketosis: individual carb tolerance varies, and protein has a small glucose-producing effect. If you need to be certain, use a blood ketone meter.
- Deficits above 25% or daily calories below about 1200 kcal (women) / 1500 kcal (men) rarely end well — you risk muscle loss, fatigue and rebound eating. The calculator warns you about both.
- If you take medication for diabetes or blood pressure, changing to a keto diet can change your needs quickly — talk to your doctor before combining it with a calorie deficit.
Practical tips
- Meet the protein target every day, especially on training days; it is the floor, not a suggestion.
- Count net carbs (total carbs minus fiber) and weigh foods for the first few weeks — covert carbs are the number one reason people don't reach ketosis.
- Weigh yourself at the same time of day and compare weekly averages, not daily numbers.
- Don't fear setting fat grams high: unlike protein and carbs, fat carries no separate physiological target on keto beyond your calorie goal. For the same logic applied to a non-keto diet, see the macros calculator.
Frequently Asked Questions
How do I calculate my keto macros by hand without a calculator?
Start with your maintenance calories (BMR × activity factor), then apply your deficit or surplus. Fix carbs first: 20 g net carbs = 80 kcal. Next, set protein: multiply your lean body mass by 1.6 g. Then compute fat from what's left: \( F = \frac{\text{calories} - 4C - 4P}{9} \), since carbs and protein provide 4 kcal per gram and fat provides 9. Example: at 1654 kcal with 20 g carbs and 84 g protein, fat is \( (1654 - 80 - 336) / 9 \approx 138 \) g.
What is a good macro percentage on keto?
A typical ketogenic split is roughly 70–75% of calories from fat, 20–25% from protein, and 5–10% from net carbs. But percentages are a byproduct, not the target — grams matter more. Two people can both eat 20 g carbs yet have different percentages because their calorie needs differ. If fat falls below about 60% of calories, the diet may not keep you in ketosis reliably.
How many net carbs per day keep me in ketosis?
Most people stay in ketosis at 20–25 g of net carbs per day. Some tolerate up to 50 g, especially if they are very active or metabolically healthy. Net carbs mean total carbs minus fiber (and often sugar alcohols), so you can subtract the fiber counted on labels in some regions. To find your personal limit, start at 20 g and increase slowly while checking with ketone strips or a blood meter.
How do I convert my results between pounds and kilograms?
If you enter weight in pounds, the calculator converts it internally: \( 1 \text{ lb} = 0.4536 \text{ kg} \). The protein target is based on lean mass in kg, but the final grams of protein, fat and carbs apply to you the same way regardless of the unit you entered — grams of food are grams of food. For height, 1 foot is 30.48 cm, so 5'5" equals about 165 cm.
Why is my protein target based on lean mass instead of total weight?
Because body fat doesn't need protein — muscle and organs do. Two people weighing 90 kg with 15% and 40% body fat have lean masses of about 76.5 kg and 54 kg, so they need very different protein amounts (at 1.6 g/kg: 122 g vs 86 g). Using total weight would overfeed protein to the leaner person and underfeed the heavier one, which matters because excess protein can slightly reduce ketosis and too little causes muscle loss in a deficit.
Can I eat too much protein on keto and get kicked out of ketosis?
For most people, no — the concern is overstated. Through gluconeogenesis your liver makes glucose from protein, but this is demand-driven, not supply-driven, so moderate protein intakes (1.2–2.2 g per kg of lean mass) rarely break ketosis. Only athletes eating very large amounts, or people with specific medical conditions, usually need to cap protein. Prioritize meeting your protein floor, especially when losing fat.
Should I recalculate my macros as I lose weight?
Yes. Your calorie needs and lean mass both shrink as you lose weight, so targets calculated at your starting weight become too generous within a couple of months. A practical rule: recalculate every 4–5 kg (about 10 lb) lost, or if your weight has stalled for 3–4 weeks despite consistent tracking. Keep protein relative to lean mass, redo your BMR with the new weight, and adjust fat to fit the new calorie target.