How accurate is this protein calculator?

It applies ranges from peer‑reviewed sources (ISSN position stand, DRIs, and Helms et al. for energy restriction). Your individual needs can vary with energy balance, training status, and health conditions.

Should I use body weight or lean body mass?

For most goals, grams per kilogram of body weight is acceptable. During aggressive fat loss, using lean body mass (via body fat %) offers a sharper estimate.

Is high protein safe for healthy adults?

Within these evidence‑based ranges, protein is generally safe for healthy adults. People with kidney or liver disease should seek medical guidance.

Do older adults need more protein?

Yes. Due to anabolic resistance, many authorities recommend 1.0–1.2 g/kg/day for healthy older adults, higher than the 0.8 g/kg RDA.

How should I split protein across meals?

Distribute evenly across 3–5 meals. Aim for roughly 0.3–0.5 g/kg per meal to optimize muscle protein synthesis.

Can endurance athletes use this tool?

Yes. The calculator includes the 1.2–1.7 g/kg/day range typically recommended for endurance training.

Does energy balance matter?

Yes. During caloric deficit, needs trend higher (especially when lean), which is why we provide a lean‑mass‑based range for fat loss.

Protein Intake Calculator | Health & Fitness Nutrition Tool

Data Source and Methodology

International Society of Sports Nutrition (ISSN) Position Stand: Protein and exercise. Jäger R, Kerksick CM, Campbell BI, et al. Journal of the International Society of Sports Nutrition. 2017. Read
Dietary Reference Intakes for Protein and Amino Acids. Institute of Medicine (National Academies), 2005. Read
Protein and amino acid requirements in human nutrition. WHO/FAO/UNU Expert Consultation, 2007. Read
Evidence-based recommendations for natural bodybuilding contest preparation. Helms ER, Aragon AA, Fitschen PJ. JISSN. 2014. Read
Morton RW et al. A systematic review and meta-analysis of protein supplementation and resistance training. Br J Sports Med. 2018. Read

All calculations are strictly derived from the ranges and formulas summarized from these sources to address common goals (health, hypertrophy, endurance, fat loss, pregnancy and lactation).

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

Formulas Explained

Unit conversion: \( \text{kg} = \frac{\text{lb}}{2.20462} \)

Lean body mass (optional): \( \text{LBM}_{kg} = \text{Weight}_{kg} \times (1 - \frac{\text{BodyFat}\%}{100}) \)

General health: \( \text{Protein} = \text{BW}_{kg} \times r, \quad r \in [0.8,\,1.2] \)

Endurance: \( \text{Protein} = \text{BW}_{kg} \times r, \quad r \in [1.2,\,1.7] \)

Strength/Muscle gain: \( \text{Protein} = \text{BW}_{kg} \times r, \quad r \in [1.6,\,2.2] \)

Fat loss (if LBM known): \( \text{Protein} = \text{LBM}_{kg} \times r, \quad r \in [2.3,\,3.1] \)

Fat loss (if LBM unknown): \( \text{Protein} = \text{BW}_{kg} \times r, \quad r \in [1.8,\,2.4] \)

Pregnancy: \( \text{Protein} = 1.1 \times \text{BW}_{kg} \)

Lactation: \( \text{Protein} = 1.3 \times \text{BW}_{kg} \)

For athletic goals, the tool can add a small increment (up to +0.2 g/kg) based on weekly training frequency.

Glossary of Variables

BW (Body Weight): Your total body mass, in kilograms.
LBM (Lean Body Mass): Body weight excluding fat mass, estimated via body fat percentage.
r (g/kg): Evidence-based protein multiplier per kilogram, determined by your goal and training.
Daily range: Lower to upper recommended grams per day for your profile.
Target intake: Midpoint of the range, adjusted for training when applicable.
Per‑meal suggestion: Target grams divided across 3–4 meals to help distribution.

How It Works: A Step‑by‑Step Example

Scenario: Female, 28 years, 62 kg, body fat 24%, goal = Muscle gain, training 4–5 days/week.

Compute LBM (optional here, not required for gain): \( \text{LBM} = 62 \times (1 - 0.24) = 47.1 \text{ kg}\) (informational).
Select range for strength: \( r \in [1.6, 2.2] \, \text{g/kg}\).
Add training increment (4–5 d/wk → +0.15 g/kg): \( r \in [1.75, 2.35] \).
Daily grams by BW: Lower = \(62 \times 1.75 = 109 \) g; Upper = \(62 \times 2.35 = 146 \) g.
Target (midpoint) ≈ \( (109 + 146) / 2 = 127.5 \) g ≈ 128 g/day.
Per‑meal (4 meals): \( 128 / 4 = 32 \) g per meal.

Frequently Asked Questions (FAQ)

Is this medical advice?

No. This tool provides educational estimates for healthy adults. Consult your clinician for personalized advice, especially if pregnant, lactating, or managing a medical condition.

Why do fat‑loss recommendations use lean body mass?

During energy restriction, protein needs align more closely with lean tissue. Using LBM helps preserve muscle while dieting.

What if I don’t know my body fat percentage?

Leave it blank. The calculator will estimate using total body weight and show a note explaining the assumption.

Are higher intakes better for muscle gain?

Benefits plateau around 1.6–2.2 g/kg/day for most. Beyond that, gains are marginal for many, though ranges can shift with energy status and lean mass.

How should older adults adjust?

Consider 1.0–1.2 g/kg/day for general health due to anabolic resistance, and distribute protein evenly across meals.

Does protein timing matter?

Even distribution across 3–5 meals and a protein‑rich meal post‑exercise can support muscle protein synthesis.

Can endurance athletes follow the same range daily?

Yes, 1.2–1.7 g/kg/day is typical. On very high‑volume days, aim for the upper end.

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