{
  "entity_type": "unit_conversion_page",
  "id": "days-to-years",
  "name": "Days to Years (365 days)",
  "title": "Days to Years (365 days) Converter (d to yr)",
  "description": "Convert days to years (365 days): 1 d = 0.00273973 yr. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.",
  "quantity": "time",
  "quantity_name": "Time",
  "base_unit": "s",
  "from_unit": {
    "symbol": "day",
    "display": "d",
    "name": "days",
    "singular": "day"
  },
  "to_unit": {
    "symbol": "year_365",
    "display": "yr",
    "name": "years (365 days)",
    "singular": "year"
  },
  "linear": true,
  "factor": 0.002739726027,
  "inverse_factor": 365,
  "formula": "years (365 days) = days × 0.002739726027",
  "reverse_formula": "days = years (365 days) × 365",
  "unit_relation": "1 d = 0.00273973 yr",
  "examples": [
    {
      "value": 5,
      "result": 0.0136986,
      "text": "5 d = 0.0136986 yr"
    },
    {
      "value": 12.5,
      "result": 0.0342466,
      "text": "12.5 d = 0.0342466 yr"
    },
    {
      "value": 100,
      "result": 0.273973,
      "text": "100 d = 0.273973 yr"
    }
  ],
  "table": [
    {
      "day": 1,
      "year_365": 0.00273973
    },
    {
      "day": 2,
      "year_365": 0.00547945
    },
    {
      "day": 3,
      "year_365": 0.00821918
    },
    {
      "day": 4,
      "year_365": 0.0109589
    },
    {
      "day": 5,
      "year_365": 0.0136986
    },
    {
      "day": 6,
      "year_365": 0.0164384
    },
    {
      "day": 7,
      "year_365": 0.0191781
    },
    {
      "day": 8,
      "year_365": 0.0219178
    },
    {
      "day": 9,
      "year_365": 0.0246575
    },
    {
      "day": 10,
      "year_365": 0.0273973
    },
    {
      "day": 15,
      "year_365": 0.0410959
    },
    {
      "day": 20,
      "year_365": 0.0547945
    },
    {
      "day": 25,
      "year_365": 0.0684932
    },
    {
      "day": 30,
      "year_365": 0.0821918
    },
    {
      "day": 40,
      "year_365": 0.109589
    },
    {
      "day": 50,
      "year_365": 0.136986
    },
    {
      "day": 75,
      "year_365": 0.205479
    },
    {
      "day": 100,
      "year_365": 0.273973
    },
    {
      "day": 200,
      "year_365": 0.547945
    },
    {
      "day": 250,
      "year_365": 0.684932
    },
    {
      "day": 500,
      "year_365": 1.36986
    },
    {
      "day": 1000,
      "year_365": 2.73973
    }
  ],
  "faq": [
    {
      "q": "How many years (365 days) are in one day?",
      "a": "1 d = 0.00273973 yr. 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 days to years (365 days)?",
      "a": "Multiply the value in days by 0.002739726027: years (365 days) = days × 0.002739726027. For example, 5 d = 0.0136986 yr."
    },
    {
      "q": "How do I convert years (365 days) back to days?",
      "a": "Multiply by the inverse factor 365 (days = years (365 days) × 365), or use the years (365 days)-to-days 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=day&to_unit=year_365",
    "calculator": "https://tttkmbb.com/api/v1/calculate/time?value=5&from_unit=day&to_unit=year_365",
    "mcp_tool": "convert_units",
    "mcp_arguments": {
      "value": 5,
      "from_unit": "day",
      "to_unit": "year_365"
    }
  },
  "links": {
    "html": "https://tttkmbb.com/conversion/days-to-years",
    "markdown": "https://tttkmbb.com/conversion/days-to-years.md",
    "json": "https://tttkmbb.com/conversion/days-to-years.json",
    "reverse": "https://tttkmbb.com/conversion/years-to-days",
    "quantity_converter": "https://tttkmbb.com/conversion/time",
    "units": "https://tttkmbb.com/api/v1/units?quantity=time"
  },
  "timestamp": "2026-09-24"
}