Protein calculator

How to use the calculator

1. Enter your body weight in kilograms (decimals use a period, for example 80.5).
2. Choose the goal you are training for now, not the one you plan to reach.
3. Press "Calculate" and take the range, not a single number.
4. Start from the middle of the range and adjust by how you feel, your weight trend and how well you tolerate training.

Where the ranges come from

For exercising adults, position stands and reviews give spans of values rather than a single requirement, so the calculator produces a range:

• ACSM/AND/DC (position statement, 2016): 1.2–2.0 g of protein per kg of body weight per day depending on training volume and type.
• ISSN (position stand, 2017): 1.4–2.0 g per kg per day is enough for most trainees; in a main meal, 20–25 g (~0.25 g/kg) every 3–4 hours.
• The Morton et al. meta-regression (2018, 49 studies): muscle mass gains plateau at about 1.6 g per kg per day — above that, gains do not rise.
• In a calorie deficit, protein needs are higher: Longland et al. (2016) — 2.4 g per kg per day in a large deficit with training preserved and built muscle versus 1.2 g per kg; Mettler et al. (2010) — higher protein reduces muscle loss during weight loss.

Hence the calculator's goals: maintenance — the lower part of the general range (1.2–1.6); muscle gain — from the plateau to the upper boundary found in the literature (1.6–2.2); weight loss — with a raised upper boundary from deficit studies (1.6–2.4). All three are estimated spans for healthy exercising adults, not requirements and not a prescription.

Assumptions

• The calculation is based on kilograms of total body weight: body composition (the share of muscle and fat) is not taken into account. With a high fat mass it is sensible to aim at the lower part of the range.
• There is one goal and it is chosen by the user. For a mixed task (gaining muscle at a slight deficit) the reference is the overlap of the ranges, about 1.6–2.2 g per kg, with attention to the weight trend.
• Within the tool's boundaries the range does not distinguish sex or age: the position stands for exercising adults do not set separate requirements for men and women.
• A weight of 35–200 kg is the limit of the tool, not a medical assessment.
• The range describes total intake per day; distribution across meals is a secondary reference (see the example below).

How to check it by hand

Weight 70 kg, goal "muscle gain" (range 1.6–2.2 g per kg):

1. Lower boundary: 70 × 1.6 = 112 g of protein per day.
2. Upper boundary: 70 × 2.2 = 154 g of protein per day.
3. Middle of the range: (112 + 154) / 2 = 133 g per day.

The calculator shows values rounded to the nearest 5 g (a practical step for a food reference): 112 → 110 g, 154 → 155 g, the middle 133 → 135 g. The arithmetic above is the exact calculation before rounding.

The same weight with other goals: maintenance 70 × 1.2 = 84 and 70 × 1.6 = 112 → 84–112 g (in the calculator 85–110 g); weight loss 70 × 1.6 = 112 and 70 × 2.4 = 168 → 112–168 g (in the calculator 110–170 g).

Example split across meals

This is distribution arithmetic, not a meal plan: the calculator does not build a diet and does not name foods.

Suppose the exact reference is 112–154 g per day (weight 70 kg, goal "muscle gain"; the calculator shows the same numbers rounded to 5 g — 110–155 g). Divide the daily span by the number of meals: over 4 meals, 112 / 4 = 28 and 154 / 4 = 38.5, so about 30–40 g of protein in a main meal; over 3 meals, about 37–51 g per meal.

The same rule in terms of body weight: 0.4 g per kg per meal × 4 meals = 1.6 g per kg per day (the lower boundary), while the upper boundary of 2.2 g per kg is covered by meals of 0.55 g per kg. The general reference points from the position stands and reviews: at least 20–25 g of protein in a main meal and gaps of about 3–4 hours. Choose the exact foods, portions and meal times to suit your routine yourself — the calculator is responsible only for the daily range.

Limitations

• This is an estimated range, not a medical prescription and not a meal plan: for kidney disease and the other conditions in the warning at the top of the page, the protein intake is determined by a doctor or dietitian.
• A calculation per kg of weight does not account for body composition; with a noticeable fat mass, aim at the lower part of the range.
• The range does not set protein quality: the daily total matters first, then the distribution across meals.
• A daily reference does not replace an assessment of total calories: body composition changes with the overall energy balance, not protein on its own.
• A sudden jump to the upper boundary does not speed up muscle gain: gains plateau at about 1.6 g per kg per day; start from the middle of the range.
• The input boundaries (35–200 kg) are the limits of the tool, not a medical assessment; outside them, see a specialist.