{
  "id": "creatine",
  "version": "a57b48352d9b",
  "status": "published",
  "name": "Creatine Calculator",
  "question": "How much creatine should I take?",
  "summary": "Works out a creatine monohydrate loading dose from body weight (0.3 g per kg a day in four doses for 5 to 7 days) and the maintenance and no-loading doses from the ISSN position stand.",
  "category": "health",
  "subcategory": "nutrition",
  "url": "https://www.acalculator.org/health/creatine-calculator",
  "markdown": "https://www.acalculator.org/health/creatine-calculator.md",
  "kind": "function",
  "method": "Loading per day = 0.3 g × body weight in kg, in four equal doses, for 5 to 7 days; then 3 to 5 g a day.",
  "assumptions": [
    "Doses are for creatine monohydrate in healthy adults, as in the ISSN position stand.",
    "Loading is optional: 3 g a day for 28 days fills muscle creatine stores without it.",
    "1 lb = 0.45359237 kg exactly."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "u": {
        "title": "Weight in",
        "description": "Kilograms or pounds.",
        "type": "string",
        "enum": [
          "lb",
          "kg"
        ]
      },
      "wt": {
        "title": "Body weight (lb)",
        "description": "Your body weight in pounds.",
        "type": "number",
        "minimum": 1,
        "maximum": 2200
      },
      "wtkg": {
        "title": "Body weight (kg)",
        "description": "Your body weight in kilograms.",
        "type": "number",
        "minimum": 1,
        "maximum": 1000
      }
    }
  },
  "outputs": {
    "loadDay": {
      "label": "Loading dose per day (g)",
      "description": "0.3 g per kg of body weight a day, for 5 to 7 days.",
      "format": "number"
    },
    "loadDose": {
      "label": "Each of 4 daily doses (g)",
      "description": "The daily loading dose split into four equal doses.",
      "format": "number"
    },
    "loadMin": {
      "label": "Loading total over 5 days (g)",
      "description": "The daily loading dose × 5.",
      "format": "number"
    },
    "loadMax": {
      "label": "Loading total over 7 days (g)",
      "description": "The daily loading dose × 7.",
      "format": "number"
    },
    "kg": {
      "label": "Body weight (kg)",
      "description": "Body weight in kilograms (1 lb = 0.45359237 kg).",
      "format": "number"
    },
    "maintenance": {
      "label": "Maintenance dose",
      "description": "The daily dose after loading, from the ISSN position stand.",
      "format": "text"
    },
    "noLoad": {
      "label": "Without loading",
      "description": "The ISSN alternative to loading: 3 g a day for 28 days (84 g in all).",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "u": "lb",
      "wt": 170,
      "wtkg": 77
    },
    "outputs": {
      "loadDay": 23.13321087,
      "loadDose": 5.7833027175,
      "loadMin": 115.66605435,
      "loadMax": 161.93247609,
      "kg": 77.1107029,
      "maintenance": "3 to 5 g a day",
      "noLoad": "3 g a day for 28 days"
    },
    "text": "Load with about 23.1 g a day (5.8 g four times a day) for 5 to 7 days, then take 3 to 5 g a day."
  },
  "examples": [
    {
      "given": {
        "u": "kg",
        "wtkg": 70
      },
      "expect": {
        "loadDay": 21,
        "loadDose": 5.25,
        "loadMin": 105,
        "loadMax": 147,
        "kg": 70
      },
      "source": "hand calculation in content.mdx: 0.3 × 70 = 21; 21 ÷ 4 = 5.25; Kreider RB et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine, J Int Soc Sports Nutr 2017;14:18 (loading about 0.3 g/kg a day, 5 g four times daily, for 5–7 days; maintenance 3–5 g/day; or 3 g/day for 28 days), https://pmc.ncbi.nlm.nih.gov/articles/PMC5469049/"
    },
    {
      "given": {
        "u": "lb",
        "wt": 170
      },
      "expect": {
        "loadDay": 23.13321087,
        "loadDose": 5.7833027175,
        "kg": 77.1107029
      },
      "source": "hand calculation in content.mdx: 170 × 0.45359237 = 77.1107029 kg; × 0.3 = 23.13321087 g; Python 3: Fraction; Kreider RB et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine, J Int Soc Sports Nutr 2017;14:18 (loading about 0.3 g/kg a day, 5 g four times daily, for 5–7 days; maintenance 3–5 g/day; or 3 g/day for 28 days), https://pmc.ncbi.nlm.nih.gov/articles/PMC5469049/"
    },
    {
      "given": {
        "u": "kg",
        "wtkg": 55.5
      },
      "expect": {
        "loadDay": 16.65,
        "loadDose": 4.1625,
        "maintenance": "3 to 5 g a day"
      },
      "source": "hand calculation in content.mdx: 0.3 × 55.5 = 16.65; ÷ 4 = 4.1625; Kreider RB et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine, J Int Soc Sports Nutr 2017;14:18 (loading about 0.3 g/kg a day, 5 g four times daily, for 5–7 days; maintenance 3–5 g/day; or 3 g/day for 28 days), https://pmc.ncbi.nlm.nih.gov/articles/PMC5469049/"
    }
  ],
  "sources": [
    "Kreider RB, Kalman DS, Antonio J and others. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. doi:10.1186/s12970-017-0173-z (loading with 5 g, about 0.3 g/kg, four times daily for 5–7 days; maintenance 3–5 g/day; alternative 3 g/day for 28 days). https://pmc.ncbi.nlm.nih.gov/articles/PMC5469049/ (retrieved 2026-10-19)",
    "NIST Special Publication 811 (2008), Appendix B.8: 1 lb = 0.45359237 kg exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-19)"
  ],
  "related": [
    "protein",
    "caffeine"
  ],
  "changelog": []
}