{
  "id": "protein",
  "version": "29a2e547419e",
  "status": "published",
  "name": "Protein Calculator",
  "question": "How much protein do I need a day?",
  "summary": "Estimates grams of protein a day from body weight and a sourced range per kilogram: the adult RDA, older adults, pregnancy, breastfeeding, regular exercise, or building muscle.",
  "category": "health",
  "subcategory": "nutrition",
  "url": "https://www.acalculator.org/health/protein-calculator",
  "markdown": "https://www.acalculator.org/health/protein-calculator.md",
  "kind": "function",
  "method": "Protein a day (g) = body weight (kg) × grams per kilogram for the goal; ranges use their middle value.",
  "assumptions": [
    "Grams per kilogram a day: most adults 0.8 (RDA); 65 and older 1.0 to 1.2; pregnant 1.1; breastfeeding 1.3; regular exercise 1.4 to 2.0; building muscle 1.6 to 2.2.",
    "The daily figure is the middle of the range; the low and high ends are shown too.",
    "Weight is total body weight. For people with a lot of body fat, a dietitian may use a lower reference weight.",
    "Protein gives 4 calories per gram.",
    "This is an estimate for planning, not medical advice."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "weight": {
        "title": "Weight",
        "description": "Your body weight.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "minimum": 20,
        "maximum": 700
      },
      "goal": {
        "title": "Who is it for?",
        "description": "The group or goal, which sets the grams of protein per kilogram of body weight.",
        "type": "string",
        "enum": [
          "rda",
          "older",
          "pregnant",
          "breastfeeding",
          "active",
          "muscle"
        ]
      }
    }
  },
  "outputs": {
    "protein": {
      "label": "Protein a day",
      "description": "Grams of protein a day: body weight × the middle of the range for the goal.",
      "format": "quantity",
      "unit": "g"
    },
    "low": {
      "label": "Range from",
      "description": "The low end of the range: body weight × the lower grams per kilogram.",
      "format": "quantity",
      "unit": "g"
    },
    "high": {
      "label": "Range up to",
      "description": "The high end of the range: body weight × the higher grams per kilogram.",
      "format": "quantity",
      "unit": "g"
    },
    "rate": {
      "label": "Per kilogram",
      "description": "The grams per kilogram (and per pound) used.",
      "format": "text"
    },
    "calories": {
      "label": "Calories from this protein",
      "description": "Calories a day from the protein: grams × 4.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "weight": 68.0388555,
      "goal": "rda"
    },
    "outputs": {
      "protein": 0.0544310844,
      "rate": "0.8 g per kg of body weight, or 0.36 g per lb",
      "calories": 217.7243376
    },
    "text": "Aim for about 54 g of protein a day (0.8 g per kg of body weight, or 0.36 g per lb)."
  },
  "examples": [
    {
      "given": {
        "weight": 68.0388555,
        "goal": "rda"
      },
      "expect": {
        "protein": 0.0544310844,
        "rate": "0.8 g per kg of body weight, or 0.36 g per lb",
        "calories": 217.7243376
      },
      "source": "IOM 2005 protein RDA, 0.8 g/kg a day; hand calculation in content.mdx"
    },
    {
      "given": {
        "weight": 70,
        "goal": "active"
      },
      "expect": {
        "protein": 0.119,
        "low": 0.098,
        "high": 0.14,
        "calories": 476
      },
      "source": "ISSN position stand (Jäger et al. 2017), 1.4 to 2.0 g/kg a day; hand calculation in content.mdx"
    },
    {
      "given": {
        "weight": 80,
        "goal": "older"
      },
      "expect": {
        "protein": 0.088,
        "low": 0.08,
        "high": 0.096
      },
      "source": "PROT-AGE Study Group (Bauer et al. 2013), 1.0 to 1.2 g/kg a day; hand calculation in content.mdx"
    },
    {
      "given": {
        "weight": 65,
        "goal": "pregnant"
      },
      "expect": {
        "protein": 0.0715,
        "rate": "1.1 g per kg of body weight, or 0.50 g per lb"
      },
      "source": "IOM 2005 protein RDA in pregnancy, 1.1 g/kg a day; hand calculation in content.mdx"
    },
    {
      "given": {
        "weight": 90.718474,
        "goal": "muscle"
      },
      "expect": {
        "protein": 0.17236510060000002,
        "low": 0.14514955840000002,
        "high": 0.1995806428
      },
      "source": "Morton et al. 2018 (gains plateau at 1.62 g/kg, 95% CI up to 2.20); hand calculation in content.mdx"
    }
  ],
  "sources": [
    "Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005 (protein RDA 0.8 g/kg a day for adults, 1.1 in pregnancy, 1.3 in lactation). https://www.nationalacademies.org/publications/10490",
    "Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. https://doi.org/10.1016/j.jamda.2013.05.021",
    "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. https://doi.org/10.1186/s12970-017-0177-8",
    "Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. https://doi.org/10.1136/bjsports-2017-097608",
    "U.S. Code of Federal Regulations, 21 CFR 101.9(c)(1)(i)(C): 4 calories per gram of protein. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9"
  ],
  "related": [
    "macro",
    "calorie",
    "tdee",
    "bmi"
  ],
  "changelog": []
}