Protein Intake Calculator
Multiply body weight by grams-per-kilogram rate to estimate daily protein intake in grams.
What this tool does
This calculator estimates daily protein intake in grams by multiplying body weight in kilograms by a user-selected grams-per-kilogram rate (0.8–3.0 g/kg). The default of 1.8 g/kg sits in the upper half of the 1.2–2.0 g/kg range that the 2016 joint position statement of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine gives for athletes. The output provides total daily protein intake and per-meal portions, though individual requirements may vary based on training volume, body composition goals, and metabolic factors.
Formula Used
Disclaimer
This calculator is for educational and informational purposes only. It does not provide medical, nutritional, or training advice. Results are mathematical estimates and may not reflect individual circumstances. Consult a qualified coach, registered dietitian, medical professional, or physiotherapist for personal guidance.
How Protein Intake Calculator works
This calculator multiplies body weight in kilograms by a user-selected grams-per-kilogram rate to estimate total daily protein intake in grams. The default rate of 1.8 g/kg sits inside the athlete ranges published by the Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM (1.2–2.0 g/kg) and the International Society of Sports Nutrition (1.4–2.0 g/kg for building or maintaining muscle), toward the upper end of both. The tool allows adjustment from 0.8 g/kg (the RDA for sedentary adults) up to 3.0 g/kg (higher end for specific athletic or body-composition goals). The result appears as grams per day, plus a per-meal breakdown assuming four meals.
The formula
Daily protein (g) = Body weight (kg) × Grams per kilogram rate
Body weight is entered in kilograms. The grams-per-kilogram rate is selected based on training status, goal, and individual context. Multiplying these two values produces the estimated daily protein intake in grams. Worked through with the defaults, 75 kg at 1.8 g/kg gives 135 g per day, which the tool also divides by four to show roughly 34 g per meal if intake is spread evenly.
Where this method is most accurate
The linear grams-per-kilogram model aligns well with nitrogen-balance and whole-body protein-synthesis studies in healthy adults engaged in resistance or endurance training. It is less precise for individuals at the extremes of body composition (very high or very low body fat) because lean body mass (not total mass) drives protein requirements more directly. The 0.8 g/kg lower bound corresponds to the RDA for sedentary adults; values above 1.6 g/kg are supported for athletes in hypocaloric states or during periods of high training volume.
What this tool does not do
This calculator does not account for lean body mass, activity level, caloric deficit or surplus, training phase, injury recovery, or medical conditions that alter protein metabolism. It does not provide meal timing, food selection, or supplement recommendations. It is an arithmetic multiplier, not a prescription. Individual requirements vary based on genetics, gut health, and amino acid absorption efficiency, all factors outside the scope of a simple kg × g/kg equation.
Disclaimer
This tool is for educational and informational purposes only. It is not medical, nutritional, or training advice. Consult a registered dietitian, sports nutritionist, or physician before making changes to diet or exercise routines, especially if managing a health condition or taking medication.
Questions
- Why does the calculator default to 1.8 g/kg?
- The 1.8 g/kg default sits inside the athlete ranges published by both major position statements without being a specific recommendation from either: the Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM give 1.2–2.0 g/kg, and the International Society of Sports Nutrition gives 1.4–2.0 g/kg for building or maintaining muscle. At 1.8 the default sits in the upper half of both, a deliberate starting point for exploration rather than a target.
- Should the rate be based on total body weight or lean mass?
- This calculator uses total body weight because that is the input requested. Lean-mass-based calculations are more precise but require body-composition measurement. For individuals with high body fat, multiplying total weight by a standard rate may overestimate requirements.
- What is the 0.8 g/kg lower limit based on?
- 0.8 g/kg is the Recommended Dietary Allowance (RDA) for protein established by the U.S. Institute of Medicine for sedentary adults. It represents the intake sufficient to meet the needs of 97–98% of healthy individuals in nitrogen balance.
- Why does the tool show per-meal intake divided by four?
- The per-meal calculation assumes four evenly spaced meals across the day. This is an arbitrary split for convenience; actual meal frequency and distribution depend on schedule, preference, and training timing. Muscle protein synthesis studies show benefit from spreading intake, but optimal frequency remains debated.
- Can I use pounds instead of kilograms?
- The calculator requires kilograms because the grams-per-kilogram rates in the scientific literature are reported in metric units. To convert pounds to kilograms, divide by 2.205 before entering the value.
Sources & Methodology
Multiplies body weight in kilograms by a user-selected grams-per-kilogram rate (0.8–3.0 g/kg). The default of 1.8 g/kg sits in the upper half of the athlete ranges given by the Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM (1.2–2.0 g/kg, 2016) and the International Society of Sports Nutrition (1.4–2.0 g/kg, 2017); the 0.8 g/kg floor is the Institute of Medicine RDA. Per-meal figures divide the daily total by four.
- › Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016;116(3):501-528.
- › Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
- › Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005.
Spotted something off?
Calculations or display — let us know.
More in Macros & Intake
View all 10 →- Calorie Deficit PlannerWork backwards from a target date to the daily calorie deficit and intake the timeline implies.
- Macro Split CalculatorConvert calorie percentages into daily protein, carb, and fat gram targets based on your TDEE.
- Meal PlannerBuild a day of meals from 300+ common foods and see calories and macros add up against the targets you set.
- Alcohol Calories CalculatorEstimate the caloric contribution of ethanol in alcoholic beverages using ABV and serving size.
- Caffeine Half-Life CalculatorEstimate remaining caffeine in your system using exponential decay and a 5-hour half-life.
- Dietary Fiber Reference CalculatorRestate the commonly cited 14 g per 1,000 kcal fibre guideline at any calorie intake.