Protein Requirement by Goal Calculator
Daily protein needs vary with body weight and fitness goal. For a sedentary adult maintaining weight, the NIH Dietary Reference Intake (DRI) recommends a minimum of 0.8 g of protein per kg of body weight. Active individuals and athletes benefit from higher intakes. For muscle building (hypertrophy), the American College of Sports Medicine (ACSM) position stand supports 1.6-2.2 g/kg per day. During a calorie deficit (cutting phase), research supports 2.2 g/kg or higher to minimise muscle loss. Enter your body weight in kilograms and select your goal; the calculator applies the appropriate factor and shows daily protein in grams as well as approximate protein calories.
Protein requirement formula
Protein (g/day) = Body weight (kg) * g/kg factor
Protein calories = Protein (g/day) * 4
The g/kg factor depends on your goal: 0.8 (sedentary), 1.4 (active maintenance), 1.8 (muscle building), or 2.2 (cutting). Protein provides 4 kcal per gram.
Choosing the right protein target
- 0.8 g/kg: the minimum RDA for sedentary adults to prevent deficiency (NIH DRI).
- 1.4 g/kg: suitable for endurance athletes and regularly active adults maintaining body composition.
- 1.8 g/kg: a central estimate for resistance training individuals aiming for hypertrophy, within the 1.6-2.2 g/kg ACSM range.
- 2.2 g/kg: appropriate during calorie restriction to preserve lean mass, supported by multiple controlled trials.
- Spread your protein evenly across 3-5 meals to maximise muscle protein synthesis per meal (each meal ideally containing 25-40 g of high-quality protein).
Protein requirement calculator: frequently asked questions
How much protein do I need per day to maintain muscle?
For sedentary adults maintaining body composition, the RDA is 0.8 g per kg of body weight per day, per NIH and USDA. Active individuals aiming to maintain muscle during regular exercise typically benefit from 1.2-1.6 g/kg per day.
What protein intake is recommended for muscle building?
Research published in peer-reviewed journals and summarized by ACSM supports 1.6-2.2 g/kg per day for individuals performing resistance training with a goal of muscle hypertrophy. This calculator uses 1.8 g/kg as a central estimate for the build goal.
How much protein should I eat when cutting calories?
During a calorie deficit (cutting), higher protein intakes of 2.2-3.1 g/kg of lean body mass help preserve muscle tissue. This calculator uses 2.2 g/kg of total body weight as a practical cutting target for most individuals.
Should I use lean body mass or total body weight?
Many protocols use total body weight for simplicity when body fat percentage is not known. The targets here use total body weight. If you know your lean body mass, you may prefer to apply a higher g/kg factor to lean mass only.
Is more protein always better?
Beyond approximately 2.2-3.1 g/kg per day, additional protein provides no further benefit for muscle protein synthesis in most people. Excessively high intakes displace other macronutrients and are not recommended. Healthy kidneys handle high protein diets well, but individuals with existing kidney disease should follow medical guidance.
Official sources
- NIH Office of Dietary Supplements: Protein Fact Sheet for Health Professionals.
- USDA Dietary Guidelines 2020-2025: DietaryGuidelines.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.