Estimate protein grams from body weight

The math is a multiplication: grams = weight × coefficient. The first rung takes the EFSA (2012) Population Reference Intake: 0.83 g of protein per kg body weight per day for adults, in the opinion on dietary reference values. That is close to the US RDA of 0.8 g/kg, but this tool uses 0.83, not the RDA. The “active” rung uses 1.2 g/kg: not an EFSA PRI, an intermediate tool rung between the PRI and sports ranges. The “strength” rung uses 1.6 g/kg as a midpoint of the 1.4–2.0 g/kg interval discussed in the ISSN 2017 position stand on protein and exercise — not “the” ISSN dose, and not the top of the range (2.0). Matching energy assumes 4 kcal/g.

protéines (g/j) = poids(kg) × {0,83 | 1,2 | 1,6}

kcal issues des protéines = grammes × 4

EFSA sets a PRI of 0.83 g/kg/day for healthy adults, distinct from a body-composition goal. ISSN discusses higher intakes in people who train, often summarized as 1.4 to 2.0 g/kg/day in that position stand. We do not pull other figures from those texts (no “2.2 g/kg,” no peri-workout timing). 1.6 g/kg is a teaching example in the center of 1.4–2.0. 1.2 g/kg is claimed as neither EFSA nor ISSN. Kidney or liver disease, or a medical high-protein diet, have no place on this form.

Weight

The EFSA PRI is expressed per kg of body weight. A very high BMI or sarcopenic obesity makes this denominator debatable; the tool does not adjust.

Reference

The “strength” label does not check that you lift. It is the 1.6 g/kg rung, an example.

Assumptions

• Weight = total mass on the scale.
• Dietary protein of “normal” digestibility in the sense of the reference opinions, without a DIAAS adjustment.
• Rung chosen by you, not inferred from a training questionnaire.

Limits

• No lean mass, age, or sex in the calculation.
• 1.2 g/kg is not an EFSA or ISSN figure.
• 1.6 g/kg does not exhaust the 1.4–2.0 range.
• Does not say how to spread intakes through the day.
• Medical contraindications are not screened.

The 0.83 g/kg PRI is a population reference to avoid inadequacy in healthy adults, not an athletic ceiling. Moving to 1.6 g/kg in the tool does not “officially” raise your need: it applies an ISSN-range example. Then cross with the calorie budget (calories page): 115 g of protein is already ≈ 460 kcal, which has to fit in the total.

• Reading 1.6 g/kg as “ISSN recommends 1.6 for everyone.”

  ISSN discusses a 1.4–2.0 range for exercise. 1.6 is our midpoint example, labeled as such.

• Using a goal weight instead of current weight.

  PRI and sports g/kg are generally on current weight, sometimes on lean mass in clinic — which we do not have.

• Stacking PRI + ISSN “to be safe.”

  Rungs are alternatives, not additives. 0.83 + 1.6 has no meaning.

• Macro calculatorThe tool applies an energy percent to the calories you type, then converts with 4 kcal/g for protein and carbohydrate and 9 kcal/g for fat. These are templates, not a care plan.
• Calorie calculatorThree steps: Mifflin-St Jeor resting burn, times a lump activity factor, then a goal offset. The result is an estimate, not a diet.
• TDEE calculatorTDEE here is Mifflin-St Jeor resting metabolism times an activity factor. It includes no deficit, no surplus, and no 1,200 kcal floor.
• One-rep max (Epley)A load and a rep count (1 to 12). The tool applies Epley, not a true single-attempt max.
• Water intakeTwo distinct figures: a 35 ml per kilogram rule of thumb, optionally raised by an internal activity bonus, and the EFSA 2010 adequate intake (2.0 L/day women, 2.5 L/day men, water from drinks and foods). Neither is an order.
• Running pacePace is total time divided by distance. Average speed is the inverse. No calories are estimated: ACSM METs are not applied here.

Written by Rédaction HexaCalc (editorial team). Content last updated: August 25, 2026. No third-party medical or financial review is claimed.

• Scientific Opinion on Dietary Reference Values for protein (2012) — European Food Safety Authority (EFSA)
• Jäger R, Kerksick CM, Campbell BI, et al. — International Society of Sports Nutrition Position Stand: protein and exercise (2017) — Journal of the International Society of Sports Nutrition