{
  "id": "ppm",
  "version": "f72f8bbde991",
  "status": "published",
  "name": "PPM Calculator",
  "question": "How many ppm is it?",
  "summary": "Works out a concentration in parts per million (ppm) from the solute and solution masses, or converts ppm to and from ppb, percent, mg/kg and mg/L, and to mol/L with a molar mass.",
  "category": "chemistry",
  "subcategory": "solutions",
  "url": "https://www.acalculator.org/chemistry/ppm-calculator",
  "markdown": "https://www.acalculator.org/chemistry/ppm-calculator.md",
  "kind": "function",
  "method": "ppm = mass of solute ÷ mass of solution × 10⁶; ppb = ppm × 1,000; % = ppm ÷ 10,000; mg/kg = ppm; mg/L = ppm × density (kg/L); mol/L = mg/L ÷ 1,000 ÷ molar mass.",
  "assumptions": [
    "ppm, ppb and percent are by mass (mass of solute per mass of solution).",
    "mg/L needs the solution’s density; dilute water solutions are close to 1 g/mL, where 1 mg/L = 1 ppm.",
    "Arithmetic is exact on the typed decimals."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "from": {
        "title": "I know",
        "description": "Whether you know the two masses, or a concentration to convert.",
        "type": "string",
        "enum": [
          "value",
          "masses"
        ]
      },
      "c": {
        "title": "Concentration",
        "description": "The concentration you know, in the unit chosen next.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000000
      },
      "u": {
        "title": "Unit",
        "description": "The unit of the concentration: ppm, ppb, parts per trillion, percent by mass, mg/kg or mg/L.",
        "type": "string",
        "enum": [
          "ppm",
          "ppb",
          "ppt",
          "pct",
          "mgkg",
          "mgL"
        ]
      },
      "ms": {
        "title": "Mass of solute",
        "description": "The mass of the dissolved substance.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "exclusiveMinimum": 0,
        "maximum": 1000000000
      },
      "mt": {
        "title": "Mass of solution",
        "description": "The mass of the whole solution, solute included.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "exclusiveMinimum": 0,
        "maximum": 1000000000
      },
      "rho": {
        "title": "Solution density",
        "description": "The density of the solution, for mg/L. Dilute water solutions are about 1 g/mL.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "density",
        "minimum": 1,
        "maximum": 30000
      },
      "mm": {
        "title": "Molar mass (g/mol)",
        "description": "Optional: the molar mass of the solute, to show the concentration in mol/L.",
        "type": "number",
        "minimum": 0.5,
        "maximum": 10000000
      }
    }
  },
  "outputs": {
    "ppm": {
      "label": "Parts per million",
      "description": "Mass of solute ÷ mass of solution × 1,000,000.",
      "format": "number"
    },
    "ppb": {
      "label": "Parts per billion",
      "description": "ppm × 1,000.",
      "format": "number"
    },
    "percent": {
      "label": "Percent by mass",
      "description": "ppm ÷ 10,000.",
      "format": "number"
    },
    "mgL": {
      "label": "Milligrams per liter",
      "description": "ppm × density in kg/L.",
      "format": "number"
    },
    "molL": {
      "label": "Molarity",
      "description": "mg/L ÷ 1,000 ÷ molar mass: moles of solute per liter of solution.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "from": "value",
      "c": 15,
      "u": "ppb",
      "ms": 0.0005,
      "mt": 1,
      "rho": 1000
    },
    "outputs": {
      "ppm": 0.015,
      "ppb": 15,
      "percent": 0.0000015,
      "mgL": 0.015
    },
    "text": "The concentration is 0.015 ppm (0.0000015% by mass, 0.015 mg/L)."
  },
  "examples": [
    {
      "given": {
        "from": "value",
        "c": 15,
        "u": "ppb",
        "rho": 1000
      },
      "expect": {
        "ppm": 0.015,
        "ppb": 15,
        "mgL": 0.015
      },
      "source": "OpenStax, Chemistry 2e, §3.4 Other Units for Solution Concentrations (mass percentage; ppm = mass of solute ÷ mass of solution × 10⁶ ppm; ppb × 10⁹). https://openstax.org/books/chemistry-2e/pages/3-4-other-units-for-solution-concentrations, retrieved 2026-10-02, Example 3.25: 15 ppb is 0.015 ppm"
    },
    {
      "given": {
        "from": "masses",
        "ms": 0.00000375,
        "mt": 0.005,
        "rho": 1000
      },
      "expect": {
        "percent": 0.075,
        "ppm": 750
      },
      "source": "OpenStax, Chemistry 2e, §3.4 Other Units for Solution Concentrations (mass percentage; ppm = mass of solute ÷ mass of solution × 10⁶ ppm; ppb × 10⁹). https://openstax.org/books/chemistry-2e/pages/3-4-other-units-for-solution-concentrations, retrieved 2026-10-02, Example 3.22: 3.75 mg in 5.0 g is 0.075% by mass; × 10,000 = 750 ppm"
    },
    {
      "given": {
        "from": "value",
        "c": 0.5,
        "u": "pct",
        "rho": 1000,
        "mm": 58.44
      },
      "expect": {
        "ppm": 5000,
        "mgL": 5000,
        "molL": 0.08555783709787818
      },
      "source": "hand calculation in content.mdx: 0.5% × 10,000 = 5,000 ppm = 5,000 mg/L at 1 g/mL; 5 g/L ÷ 58.44 g/mol = 0.0856 mol/L; OpenStax, Chemistry 2e, §3.4 Other Units for Solution Concentrations (mass percentage; ppm = mass of solute ÷ mass of solution × 10⁶ ppm; ppb × 10⁹). https://openstax.org/books/chemistry-2e/pages/3-4-other-units-for-solution-concentrations, retrieved 2026-10-02"
    },
    {
      "given": {
        "from": "value",
        "c": 250,
        "u": "mgL",
        "rho": 1250
      },
      "expect": {
        "ppm": 200,
        "percent": 0.02
      },
      "source": "hand calculation in content.mdx: 250 mg/L ÷ 1.25 kg/L = 200 mg/kg = 200 ppm; OpenStax, Chemistry 2e, §3.4 Other Units for Solution Concentrations (mass percentage; ppm = mass of solute ÷ mass of solution × 10⁶ ppm; ppb × 10⁹). https://openstax.org/books/chemistry-2e/pages/3-4-other-units-for-solution-concentrations, retrieved 2026-10-02"
    }
  ],
  "sources": [
    "OpenStax, Chemistry 2e, §3.4 Other Units for Solution Concentrations: mass percentage; ppm = mass of solute ÷ mass of solution × 10⁶ ppm and ppb × 10⁹ ppb; Example 3.22 (3.75 mg of glucose in 5.0 g is 0.075%) and Example 3.25 (15 ppb of lead is 0.015 ppm). https://openstax.org/books/chemistry-2e/pages/3-4-other-units-for-solution-concentrations (retrieved 2026-10-02)"
  ],
  "related": [
    "concentration",
    "molarity",
    "dilution",
    "molar-mass"
  ],
  "changelog": []
}