{
  "entity_type": "unit_conversion_page",
  "id": "atm-to-bar",
  "name": "Atmospheres to Bar",
  "title": "Atmospheres to Bar Converter (atm to bar)",
  "description": "Convert atmospheres to bar: 1 atm = 1.01325 bar. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.",
  "quantity": "pressure",
  "quantity_name": "Pressure",
  "base_unit": "Pa",
  "from_unit": {
    "symbol": "atm",
    "display": "atm",
    "name": "atmospheres",
    "singular": "atmosphere"
  },
  "to_unit": {
    "symbol": "bar",
    "display": "bar",
    "name": "bar",
    "singular": "bar"
  },
  "linear": true,
  "factor": 1.01325,
  "inverse_factor": 0.9869232667,
  "formula": "bar = atmospheres × 1.01325",
  "reverse_formula": "atmospheres = bar × 0.9869232667",
  "unit_relation": "1 atm = 1.01325 bar",
  "examples": [
    {
      "value": 5,
      "result": 5.06625,
      "text": "5 atm = 5.06625 bar"
    },
    {
      "value": 12.5,
      "result": 12.6656,
      "text": "12.5 atm = 12.6656 bar"
    },
    {
      "value": 100,
      "result": 101.325,
      "text": "100 atm = 101.325 bar"
    }
  ],
  "table": [
    {
      "atm": 1,
      "bar": 1.01325
    },
    {
      "atm": 2,
      "bar": 2.0265
    },
    {
      "atm": 3,
      "bar": 3.03975
    },
    {
      "atm": 4,
      "bar": 4.053
    },
    {
      "atm": 5,
      "bar": 5.06625
    },
    {
      "atm": 6,
      "bar": 6.0795
    },
    {
      "atm": 7,
      "bar": 7.09275
    },
    {
      "atm": 8,
      "bar": 8.106
    },
    {
      "atm": 9,
      "bar": 9.11925
    },
    {
      "atm": 10,
      "bar": 10.1325
    },
    {
      "atm": 15,
      "bar": 15.1988
    },
    {
      "atm": 20,
      "bar": 20.265
    },
    {
      "atm": 25,
      "bar": 25.3313
    },
    {
      "atm": 30,
      "bar": 30.3975
    },
    {
      "atm": 40,
      "bar": 40.53
    },
    {
      "atm": 50,
      "bar": 50.6625
    },
    {
      "atm": 75,
      "bar": 75.9938
    },
    {
      "atm": 100,
      "bar": 101.325
    },
    {
      "atm": 200,
      "bar": 202.65
    },
    {
      "atm": 250,
      "bar": 253.313
    },
    {
      "atm": 500,
      "bar": 506.625
    },
    {
      "atm": 1000,
      "bar": 1013.25
    }
  ],
  "faq": [
    {
      "q": "How many bar are in one atmosphere?",
      "a": "1 atm = 1.01325 bar. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures."
    },
    {
      "q": "What is the formula to convert atmospheres to bar?",
      "a": "Multiply the value in atmospheres by 1.01325: bar = atmospheres × 1.01325. For example, 5 atm = 5.06625 bar."
    },
    {
      "q": "How do I convert bar back to atmospheres?",
      "a": "Multiply by the inverse factor 0.9869232667 (atmospheres = bar × 0.9869232667), or use the bar-to-atmospheres page."
    }
  ],
  "sources": [
    {
      "name": "NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors",
      "url": "https://www.nist.gov/pml/special-publication-811",
      "type": "standard",
      "retrieved_at": "2026-09-24"
    },
    {
      "name": "BIPM – The International System of Units (SI Brochure, 9th edition)",
      "url": "https://www.bipm.org/en/publications/si-brochure",
      "type": "standard",
      "retrieved_at": "2026-09-24"
    },
    {
      "name": "Wikipedia – Conversion of units",
      "url": "https://en.wikipedia.org/wiki/Conversion_of_units",
      "type": "reference",
      "retrieved_at": "2026-09-24"
    }
  ],
  "freshness": {
    "type": "static",
    "max_age_seconds": null,
    "note": "Fixed conversion factors (NIST/BIPM definitions); results never go stale."
  },
  "api": {
    "convert": "https://tttkmbb.com/api/v1/convert?value=5&from_unit=atm&to_unit=bar",
    "calculator": "https://tttkmbb.com/api/v1/calculate/pressure?value=5&from_unit=atm&to_unit=bar",
    "mcp_tool": "convert_units",
    "mcp_arguments": {
      "value": 5,
      "from_unit": "atm",
      "to_unit": "bar"
    }
  },
  "links": {
    "html": "https://tttkmbb.com/conversion/atm-to-bar",
    "markdown": "https://tttkmbb.com/conversion/atm-to-bar.md",
    "json": "https://tttkmbb.com/conversion/atm-to-bar.json",
    "reverse": "https://tttkmbb.com/conversion/bar-to-atm",
    "quantity_converter": "https://tttkmbb.com/conversion/pressure",
    "units": "https://tttkmbb.com/api/v1/units?quantity=pressure"
  },
  "timestamp": "2026-09-24"
}