Keto Macro Calculator
Personalize keto calories and macro targets using validated formulas, activity level, and goals for daily planning.
Your Inputs
Fields marked with an asterisk are required. All changes update results instantly.
Accepted range: 15–90 years. Age is used in energy and body fat estimations.
For Imperial units, enter feet and inches. Valid range: 120–230 cm (4′0″–7′6″).
Valid range (metric): 40–250 kg. If using Imperial, range is 90–550 lb. Values convert automatically when changing units.
Optional
If provided, Katch–McArdle will be used (more accurate). Otherwise we use Mifflin–St Jeor. If you choose protein per kg LBM without body fat %, we estimate BF% from BMI (Deurenberg et al.).
These factors scale your BMR to estimate TDEE (total daily energy expenditure).
Typical evidence-based ranges: 1.6–2.2 g/kg body weight for active individuals; 1.8–2.4 g/kg LBM on keto. Adjust to preference and satiety.
Many people remain in ketosis with 20–50 g net carbs per day. Start lower if unsure.
Your Keto Targets
BMR
—
kcal/day
TDEE
—
kcal/day
Target Calories
—
kcal/day
Lean Mass
—
kg
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.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
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)
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- Source — academic.oup.com · Accessed 2026-01-19
https://academic.oup.com/ajcn/article-abstract/51/2/241/4695085 - Overview — journals.lww.com · Accessed 2026-01-19
https://journals.lww.com/acsm-healthfitness/Fulltext/1996/10000/Essentials_of_Exercise_Physiology.9.aspx - Guidance — fao.org · Accessed 2026-01-19
https://www.fao.org/3/y5686e/y5686e00.htm - Formula — cambridge.org · Accessed 2026-01-19
https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/abs/body-mass-index-as-a-measure-of-body-fatness/25E7FE5E3773C7B1CCCEB3E590A9E6E2 - Protein range — bjsm.bmj.com · Accessed 2026-01-19
https://bjsm.bmj.com/content/52/6/376
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.