{
  "id": "molar-to-millimolar",
  "version": "92b27fc600c4",
  "status": "published",
  "name": "Molar to Millimolar Converter",
  "question": "How to convert molar to millimolar?",
  "summary": "Converts molar (M) to millimolar (mM) and back, with the exact unit definitions.",
  "category": "convert",
  "subcategory": "units",
  "url": "https://www.acalculator.org/convert/molar-to-millimolar",
  "markdown": "https://www.acalculator.org/convert/molar-to-millimolar.md",
  "kind": "formulas",
  "method": "mM = M × 1000 (the same as M ÷ 0.001)",
  "assumptions": [
    "1 molar = 1000 millimolar, from the exact definitions in NIST SP 811.",
    "Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "value": {
        "title": "Molar (M)",
        "description": "The amount in molar to convert.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "result": {
        "title": "Millimolar (mM)",
        "description": "The same amount in millimolar.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000000
      }
    }
  },
  "solve": {
    "fillAny": 1,
    "variables": [
      "value",
      "result"
    ],
    "inputsOnly": []
  },
  "outputs": {
    "value": {
      "label": "Molar (M)",
      "description": "The amount in molar to convert.",
      "format": "number"
    },
    "result": {
      "label": "Millimolar (mM)",
      "description": "The amount in millimolar.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "value": 1
    },
    "outputs": {
      "result": 1000
    },
    "text": "1 M = 1,000 mM."
  },
  "examples": [
    {
      "given": {
        "value": 1
      },
      "expect": {
        "result": 1000
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "value": 0.15
      },
      "expect": {
        "result": 150
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "result": 150
      },
      "expect": {
        "value": 0.15
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    }
  ],
  "sources": [
    "NIST SP 811 (2008), Guide for the Use of the International System of Units, Table 5 (SI prefixes) and Appendix B.8 (factors for units listed alphabetically), retrieved 2026-10-05. https://www.nist.gov/pml/special-publication-811",
    "IUPAC Compendium of Chemical Terminology (Gold Book), amount concentration: unit mol dm⁻³ or mol L⁻¹, sometimes written M, retrieved 2026-10-05. https://goldbook.iupac.org/terms/view/A00295"
  ],
  "related": [],
  "changelog": []
}