Protein Intake Calculator

How to use the protein intake calculator

Enter your body weight, pick the goal that matches how you train, and the tool returns a daily protein figure in grams. Weight takes a kilogram or pound toggle and the arithmetic runs in kilograms internally, because every published protein recommendation is expressed per kilogram of body weight. The defaults, 70 kg and the Build muscle goal, return 126 g a day so you can see the calculation before replacing them.

What the tool is doing is applying a factor drawn from published guidance to your weight; it is not assessing your diet, your health or your training, and the number that comes out is a reference point rather than a prescription. The page carries a medical disclaimer because protein needs interact with kidney function, medication and existing conditions that no calculator can see.

The goal sets the factor, and the factor is the entire story behind the result. Each of the five goals maps to a single grams-per-kilogram figure drawn from published guidance, and the multiplication never gets more complicated than that.

The bottom rung is the US Recommended Dietary Allowance, which is defined as the intake sufficient to meet the needs of nearly all healthy adults, a floor set to prevent deficiency rather than an optimum for anyone training hard. The upper rungs come from the sports nutrition literature.

The 2016 joint position stand from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine puts protein intake for athletes at 1.2 to 2.0 g/kg per day, and the International Society of Sports Nutrition position stand published by Jager and colleagues in 2017 recommends 1.4 to 2.0 g/kg for most exercising individuals building or maintaining muscle.

Read the main output alongside the band rather than as a single exact figure. The Build muscle setting lands on 126 g for a 70 kg person, and the strength-and-physique band as a whole runs roughly 1.6 to 2.2 g/kg, which is about 112 to 154 g at that weight, so the headline number sits comfortably in the middle of a range that is genuinely wide.

That width is not sloppiness in the research; it reflects real variation between people, training loads, energy intake and how much of the diet is coming from complete protein sources. Anywhere inside a published band is defensible, and moving from one end of it to the other is a smaller change than most people assume.

The table below shows all five factors and the ISSN band together across a range of body weights, so you can see the whole landscape at once.

Spreading the total across the day

It also helps to think of the daily total as something to distribute rather than hit in one sitting. The work on muscle protein synthesis points that way: Moore and colleagues reported in 2009 that the dose beyond which synthesis stopped rising in young men was around 0.25 g/kg per meal.

Areta and colleagues found in 2013 that four servings of 20 g every three hours stimulated synthesis more effectively than two servings of 40 g every six hours or eight servings of 10 g.

Schoenfeld and Aragon reviewed the question in 2018 and suggested about 0.4 g/kg per meal across at least four meals as a way to reach 1.6 g/kg a day. In practice that lands most people at roughly 20 to 40 g per meal across three or four meals.

The formula, worked line by line

The calculation is a single multiplication: body weight in kilograms times the grams-per-kilogram factor the chosen goal sets. Weight entered in pounds is converted to kilograms first so the units line up with the published guidance, all of which is expressed per kilogram. The result is a daily protein figure in grams.

What matters is where each factor comes from. The 0.8 g/kg at the bottom is the US Recommended Dietary Allowance, defined as the intake sufficient to meet the needs of nearly all healthy adults, which is a deficiency floor rather than a performance optimum.

The higher factors come from sports nutrition position stands: 1.2 to 2.0 g/kg for athletes in the 2016 joint statement from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine, and 1.4 to 2.0 g/kg for exercising individuals in the 2017 International Society of Sports Nutrition position stand by Jager and colleagues.

daily protein (g) = weight kg x goal factor (g/kg)
factors: sedentary 0.8, general 1.2, endurance 1.4,
         active 1.6, build muscle 1.8
per meal (Moore 2015): about 0.25 g/kg

Distribution matters alongside the total

Distribution matters alongside the daily total. Moore and colleagues reported in 2009 that the dose beyond which muscle protein synthesis stopped rising in young men was about 0.25 g/kg per meal, with a 90 percent confidence interval of 0.18 to 0.3.

Areta and colleagues found in 2013 that four servings of 20 g of whey every three hours over a twelve-hour recovery window stimulated synthesis more effectively than either two servings of 40 g every six hours or eight servings of 10 g every ninety minutes.

Schoenfeld and Aragon reviewed the question in 2018 and suggested about 0.4 g/kg per meal across at least four meals as a practical route to 1.6 g/kg a day. For a 70 kg person those two figures bracket a per-meal amount of 17.5 g at the Moore threshold and 28 g at the Schoenfeld and Aragon target, which is how the commonly quoted 20 to 40 g per meal came to be the working rule of thumb.

Two caveats belong on any protein number. First, these are population ranges from position stands, not individual prescriptions: the bands are wide because real requirements vary with training load, total energy intake, age, and how much of the diet comes from complete protein sources, and older adults in particular are often recommended intakes above the RDA to offset reduced anabolic sensitivity.

Second, on the kidney question: in people with healthy kidneys there is no good evidence that higher protein intake causes kidney damage. The genuine exception is people with existing kidney disease, for whom protein intake is a clinical decision. This page is general information rather than dietary advice, and a registered dietitian or your doctor is the right place to set a target that accounts for your own health.

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