Which BMR formula do you use?

If body fat % is provided, the calculator uses Katch–McArdle based on lean mass. Otherwise, it uses Mifflin–St Jeor (sex-specific).

Are the activity multipliers standard?

Yes. They align with commonly used Physical Activity Level (PAL) multipliers from FAO/WHO/UNU guidance.

How are macros chosen on keto?

Protein is set per kg of lean mass or body weight, carbs are capped (e.g., 20–50 g net), and fat fills remaining calories.

Can I use imperial units?

Yes. Toggle Metric/Imperial and values will convert instantly and precisely.

What if fat calories become negative?

This indicates your protein + carb calories exceed your target. Reduce protein density, carbs, or pick a less aggressive deficit.

Keto Macro Calculator

This professional keto calculator personalizes your calories and macronutrients (fat, protein, net carbs) using gold‑standard metabolic equations and your goal. It is designed for individuals following a ketogenic or low‑carb diet who want accurate daily targets with exceptional accessibility and mobile UX.

Your Inputs

Fields marked with an asterisk are required. All changes update results instantly.

Units

Metric Imperial

Biological sex

Male Female

Used by Mifflin–St Jeor if body fat % is not provided.

Age

Height

Weight

Body fat %

Optional

Activity level

Goal

Lose Maintain Gain

Intensity

Protein method

Daily net carbs

Your Keto Targets

BMR

—

kcal/day

TDEE

—

kcal/day

Target Calories

—

kcal/day

Lean Mass

—

Protein

— g (— kcal)

Net Carbs

— g (— kcal)

Fat

— g (— kcal)

Authoritative Content and Methodology

Data Source and Methodology

Primary references:

Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241–247. doi:10.1093/ajcn/51.2.241. Source
Katch VL, McArdle WD. Resting metabolic rate based on lean body mass. In: Essentials of Exercise Physiology. Lippincott Williams & Wilkins; multiple editions. Overview
FAO/WHO/UNU Expert Consultation. Human Energy Requirements. FAO Food and Nutrition Technical Report Series 1, 2001. Guidance
Deurenberg P, Weststrate JA, Seidell JC. Body mass index as a measure of body fatness: age- and sex-specific prediction formulas. Br J Nutr. 1991;65(2):105–114. Formula
Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training–induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384. Protein range

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Katch–McArdle (if body fat known):

LBM_{kg} = Weight_{kg} \times \left(1 - \frac{BF\%}{100}\right)

BMR = 370 + 21.6 \times LBM_{kg}

Mifflin–St Jeor (if body fat unknown):

BMR = 10 \times Weight_{kg} + 6.25 \times Height_{cm} - 5 \times Age + S

where S = 5 (male), S = -161 (female)

TDEE: TDEE = BMR \times PAL

Target Calories: Target = TDEE \times \begin{cases} (1 - d) & \text{for loss}\\ (1) & \text{for maintenance}\\ (1 + s) & \text{for gain} \end{cases}

Protein: Protein_{g} = p \times \begin{cases} LBM_{kg} & \text{if per kg LBM}\\ Weight_{kg} & \text{if per kg BW} \end{cases}

Carbs: Carbs_{g} = user\ input

Fat calories: Fat_{kcal} = Target - (4 \times Protein_{g} + 4 \times Carbs_{g})

Fat grams: Fat_{g} = \max\left(0, \frac{Fat_{kcal}}{9}\right)

Glossary of Variables

Symbol/Field	Definition
Age	Your age in years.
Sex	Biological sex; used in Mifflin–St Jeor and body fat estimation.
Height	Body height in centimeters (or feet/inches).
Weight	Body weight in kilograms (or pounds).
BF%	Body fat percentage. If provided, we use Katch–McArdle.
LBM	Lean Body Mass (kg) = Weight × (1 − BF%).
BMR	Basal Metabolic Rate (kcal/day).
PAL	Physical Activity Level multiplier.
TDEE	Total Daily Energy Expenditure (kcal/day).
Target	Calories after applying deficit or surplus.
Protein g	Grams of protein per day.
Net Carbs g	Grams of carbohydrate excluding fiber/sugar alcohols, per day.
Fat g	Grams of fat per day to meet calories.

How It Works: A Step-by-Step Example

Example person: Male, 35 years, 178 cm, 78 kg, BF% = 20%, Moderate activity (1.55), Goal: loss at 15% intensity, Protein: 1.8 g/kg LBM, Net carbs: 25 g.

LBM = 78 × (1 − 0.20) = 62.4 kg
BMR = 370 + 21.6 × 62.4 ≈ 370 + 1348. ≈ 1718 kcal
TDEE = 1718 × 1.55 ≈ 2663 kcal
Target = 2663 × (1 − 0.15) ≈ 2264 kcal
Protein = 1.8 × 62.4 ≈ 112 g → 448 kcal
Carbs = 25 g → 100 kcal
Fat kcal = 2264 − (448 + 100) = 1716 kcal → Fat ≈ 1716 / 9 ≈ 191 g
Macro % ≈ Protein 19.8%, Carbs 4.4%, Fat 75.8% of calories

Frequently Asked Questions (FAQ)

Which formula do you use if I don’t know my body fat?

Mifflin–St Jeor, which is highly validated for general populations. If you choose protein per kg LBM, we estimate BF% from BMI (Deurenberg) to avoid under-protein.

What activity level should I pick if I lift 3–4 times per week?

Choose “Moderate (1.55)”. If you have a physically demanding job as well, consider “Very (1.725)”.

Is protein too high for ketosis?

Most people remain in ketosis at 1.6–2.2 g/kg BW, especially with a carb cap. Individual response varies; monitor results and adjust.

Should I change carbs on training days?

Some prefer a small variance; others keep a fixed cap. Consistency simplifies adherence. Use the Copy Summary to store your plan.

How accurate are calories?

They are estimates. Reassess weekly with body-weight trends and adjust activity or intensity by 5–10% if progress stalls.

Can I use this for therapeutic keto?

Therapeutic/medical keto often has stricter carbohydrate limits and specific protein targets. Consult a qualified clinician.

Tool developed by Ugo Candido. Content verified by CalcDomain Expert Team.
Last reviewed for accuracy on: September 14, 2025.