{
  "slug": "insulin-carb-ratio",
  "title": "Insulin Dose & Carb Ratio Calculator",
  "heading": "Insulin Bolus Calculator",
  "category": "fitness-health",
  "url": "https://www.revenuelab.fyi/toolbox/insulin-carb-ratio",
  "summary": "Meal bolus, correction dose, and insulin sensitivity factor.",
  "description": "Combine a carbohydrate bolus with a correction dose using your insulin-to-carb ratio and correction factor, and see the sensitivity factors the 500 and 1800 rules suggest from your total daily dose.",
  "formula": "Bolus = carbs ÷ I:C ratio + (current BG − target) ÷ correction factor.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=insulin-carb-ratio",
  "inputs": [
    {
      "id": "carbs",
      "label": "Carbohydrates in meal",
      "kind": "number",
      "hint": null,
      "default": 60,
      "unit": "g",
      "min": 0,
      "max": null
    },
    {
      "id": "icr",
      "label": "Insulin-to-carb ratio (1 unit per X g)",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": null,
      "min": 1,
      "max": null
    },
    {
      "id": "bg",
      "label": "Current blood glucose",
      "kind": "number",
      "hint": null,
      "default": 180,
      "unit": "mg/dL",
      "min": 40,
      "max": null
    },
    {
      "id": "target",
      "label": "Target glucose",
      "kind": "number",
      "hint": null,
      "default": 110,
      "unit": "mg/dL",
      "min": 70,
      "max": null
    },
    {
      "id": "cf",
      "label": "Correction factor (mg/dL per unit)",
      "kind": "number",
      "hint": null,
      "default": 45,
      "unit": null,
      "min": 5,
      "max": null
    },
    {
      "id": "tdd",
      "label": "Total daily dose",
      "kind": "number",
      "hint": null,
      "default": 42,
      "unit": "units",
      "min": 1,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "total",
      "label": "Total bolus (units)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "meal",
      "label": "Meal coverage (units)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "correction",
      "label": "Correction dose (units)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "rule500",
      "label": "Suggested I:C from 500 rule",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "rule1800",
      "label": "Suggested correction factor (1800 rule)",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Carbohydrates in meal: 60 g",
      "Insulin-to-carb ratio (1 unit per X g): 12",
      "Current blood glucose: 180 mg/dL",
      "Target glucose: 110 mg/dL",
      "Correction factor (mg/dL per unit): 45",
      "Total daily dose: 42 units"
    ],
    "outputs": [
      "Total bolus (units): 6.6",
      "Meal coverage (units): 5",
      "Correction dose (units): 1.56",
      "Suggested I:C from 500 rule: 11.9",
      "Suggested correction factor (1800 rule): 43"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter carbohydrates in meal (g).",
      "Enter insulin-to-carb ratio (1 unit per x g).",
      "Enter current blood glucose (mg/dL).",
      "Enter target glucose (mg/dL).",
      "Enter correction factor (mg/dl per unit).",
      "Enter total daily dose (units).",
      "Read your total bolus (units) on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "carbs": 35,
        "icr": 7.199999999999999,
        "bg": 110,
        "target": 70,
        "cf": 25,
        "tdd": 25
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "carbs": 60,
        "icr": 12,
        "bg": 180,
        "target": 110,
        "cf": 45,
        "tdd": 42
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "carbs": 95,
        "icr": 19.200000000000003,
        "bg": 290,
        "target": 175,
        "cf": 70,
        "tdd": 67
      }
    }
  ],
  "limitations": [
    "Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.",
    "Results do not account for medical conditions, medication, or pregnancy.",
    "Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it."
  ],
  "faq": [
    {
      "q": "Should I use this to dose insulin?",
      "a": "No. Use it to understand the arithmetic and sanity-check a plan your care team set. Insulin dosing decisions belong with your clinician."
    },
    {
      "q": "Why do the 500/1800 rules differ from my settings?",
      "a": "They're starting estimates. Real ratios vary by time of day, activity, and insulin type, and get tuned from logged data."
    }
  ],
  "related": [],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Insulin Dose & Carb Ratio Calculator (https://www.revenuelab.fyi/toolbox/insulin-carb-ratio)"
}