UtilibyKeto Macro Calculator
Work out your daily calories, protein, fat and carbs for keto, low-carb, carnivore or a standard diet. Free, private and no sign-up.
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Results update as you type. Estimates only — not medical advice.
Keto Macro Calculator by Utiliby
How to use this keto macro calculator
- Pick Metric or Imperial units.
- Enter your sex, age, height and weight.
- Choose an activity level that matches a normal week, not your best week.
- Select a diet preset. Standard keto uses 25 g net carbs, strict keto 15 g, low-carb 50 g and carnivore near-zero. Pick Custom carbs to enter your own number.
- Choose a goal and, if you lift weights, raise the protein target toward 1.8–2.2 g per kilogram.
- Read your daily calories and grams of protein, fat and carbs. Use Copy results or Copy link to save the plan.
How the macros are calculated
This calculator uses the Mifflin-St Jeor equation, the most widely validated formula for estimating resting energy expenditure in healthy adults:
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
- Maintenance calories = BMR × activity factor
- Target calories = maintenance × goal multiplier (from −25% to +20%)
Macros are then split as follows:
- Carbs are fixed by the diet preset or your custom number, in grams of net carbs.
- Protein = your g/kg target × body weight in kg.
- Fat = the remaining calories after carbs and protein, divided by 9 kcal per gram.
If protein and carbs together exceed the calorie target (common on aggressive cuts), the calculator reduces fat to zero and shows a warning so you can lower protein, raise carbs or loosen the deficit.
Keto, low-carb, carnivore and standard diets
Standard keto
Around 20–30 g of net carbs per day, moderate protein and the rest of the calories from fat. This is the most common entry point and is what most people mean by "keto".
Strict keto
15 g or fewer net carbs. Used by people who are very insulin-resistant, who are doing a therapeutic ketogenic diet, or who find they feel best at a very low carb level.
Low-carb
50–100 g net carbs. Not always ketogenic, but many people find it easier to sustain while still getting most of the benefits of cutting refined carbs.
Carnivore
Effectively zero plant carbs. Protein is usually kept high and fat fills the rest. This calculator sets carbs to 1 g as a placeholder. Check with a doctor before going long-term.
Moderate carb and standard
For maintenance, athletes or anyone not wanting ketosis. Moderate carb uses 100 g and standard balances carbs at 40% of calories, protein at your g/kg target, and fat for the rest.
How much protein do you need?
Sedentary adults need roughly 0.8 g of protein per kilogram of body weight to avoid deficiency. For people who train, the range is 1.2–2.2 g/kg. Athletes and people in a calorie deficit should aim for the higher end because protein protects muscle when calories are low.
On keto, protein is often set too low by older sources. Modern low-carb practitioners usually keep protein in the 1.5–2.0 g/kg range and adjust fat to control hunger. Fat is a lever, not a target: if you are hungry, add fat; if you are trying to lose fat and feel fine, you can lower it.
Net carbs vs total carbs
Net carbs = total carbs − fiber (and on some plans, − half of sugar alcohols). Keto plans almost always count net carbs because fiber does not raise blood glucose much. This calculator asks for net carbs. If the food label in your country lists total carbs only, subtract fiber before logging.
Worked examples
Example 1 — Moderate cut on standard keto. A 35-year-old woman, 165 cm, 70 kg, moderately active, wants to lose weight at a moderate pace. Her BMR is 10×70 + 6.25×165 − 5×35 − 161 = 1,370 kcal. Maintenance is 1,370 × 1.55 = 2,124 kcal. Target at −15% is 1,805 kcal. Protein at 1.6 g/kg is 112 g (448 kcal). Carbs are 25 g (100 kcal). Fat is (1,805 − 448 − 100) ÷ 9 = 140 g.
Example 2 — Lean bulk on strict keto. A 28-year-old man, 180 cm, 80 kg, very active, wants to gain slowly. BMR = 10×80 + 6.25×180 − 5×28 + 5 = 1,790 kcal. Maintenance = 1,790 × 1.725 = 3,088 kcal. Target at +10% is 3,397 kcal. Protein at 2.0 g/kg is 160 g. Carbs are 15 g. Fat is (3,397 − 640 − 60) ÷ 9 = 300 g.
Frequently asked questions
How many carbs should I eat on keto?
Most people aim for 20 to 50 grams of net carbs per day to stay in ketosis. This calculator uses 25 grams for the standard keto preset, 15 grams for strict keto and 50 grams for a more relaxed low-carb approach.
How is the keto macro calculator calculated?
The calculator estimates your basal metabolic rate with the Mifflin-St Jeor equation, multiplies it by an activity factor to get maintenance calories, adjusts for your goal, then splits the remaining calories into protein and fat after setting carbs.
Should I use net carbs or total carbs?
Keto plans usually count net carbs, which is total carbs minus fiber. This calculator asks for net carbs. If you track total carbs instead, subtract fiber from the food label before logging.
Is a macro calculator accurate?
It is an estimate. Real needs vary with genetics, medication, thyroid function and how accurately you log food. Use the number as a starting point, track your weight and energy for two to three weeks, then adjust by 100 to 200 calories.
How much protein do I need on keto?
Most adults do well on 1.2 to 2.2 grams of protein per kilogram of body weight. Athletes and people lifting weights should stay at the higher end. The calculator lets you adjust protein per kilogram with a slider.
Does this calculator work in metric and imperial units?
Yes. Switch between metric (cm, kg) and imperial (ft/in, lb). The calculator converts internally so the results are the same either way.
Is anything I enter stored?
No. All calculations run in your browser. Nothing you type is sent to or stored on our servers.