# Hours to Years (365 days) (h to yr)

> Convert hours to years (365 days): 1 h = 0.000114155 yr. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `hours-to-years` · Quantity: Time (`time`, base unit s) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/hours-to-years · This document: https://tttkmbb.com/conversion/hours-to-years.md · JSON: https://tttkmbb.com/conversion/hours-to-years.json (add `?value=` for a result)

## Formula

- `1 h = 0.000114155 yr`
- `years (365 days) = hours × 0.0001141552511`
- Reverse: `hours = years (365 days) × 8760`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 h = 0.000570776 yr
- 12.5 h = 0.00142694 yr
- 100 h = 0.0114155 yr

## Conversion table

| Hours (h) | Years (365 days) (yr) |
| --- | --- |
| 1 | 0.000114155 |
| 2 | 0.000228311 |
| 3 | 0.000342466 |
| 4 | 0.000456621 |
| 5 | 0.000570776 |
| 6 | 0.000684932 |
| 7 | 0.000799087 |
| 8 | 0.000913242 |
| 9 | 0.0010274 |
| 10 | 0.00114155 |
| 15 | 0.00171233 |
| 20 | 0.00228311 |
| 25 | 0.00285388 |
| 30 | 0.00342466 |
| 40 | 0.00456621 |
| 50 | 0.00570776 |
| 75 | 0.00856164 |
| 100 | 0.0114155 |
| 200 | 0.0228311 |
| 250 | 0.0285388 |
| 500 | 0.0570776 |
| 1000 | 0.114155 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=h&to_unit=year_365` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"h","to_unit":"year_365"}`
- All time units: https://tttkmbb.com/api/v1/units?quantity=time · full converter: [Time Converter](https://tttkmbb.com/conversion/time.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many years (365 days) are in one hour?**

1 h = 0.000114155 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.

**What is the formula to convert hours to years (365 days)?**

Multiply the value in hours by 0.0001141552511: years (365 days) = hours × 0.0001141552511. For example, 5 h = 0.000570776 yr.

**How do I convert years (365 days) back to hours?**

Multiply by the inverse factor 8760 (hours = years (365 days) × 8760), or use the years (365 days)-to-hours page.

## Related conversions

- [Years (365 days) to hours](https://tttkmbb.com/conversion/years-to-hours.md) (reverse)
- [Hours to Minutes](https://tttkmbb.com/conversion/hours-to-minutes.md)
- [Minutes to Hours](https://tttkmbb.com/conversion/minutes-to-hours.md)
- [Minutes to Seconds](https://tttkmbb.com/conversion/minutes-to-seconds.md)
- [Seconds to Minutes](https://tttkmbb.com/conversion/seconds-to-minutes.md)
- [Days to Hours](https://tttkmbb.com/conversion/days-to-hours.md)
- [Hours to Days](https://tttkmbb.com/conversion/hours-to-days.md)
- [Weeks to Days](https://tttkmbb.com/conversion/weeks-to-days.md)
- [Days to Weeks](https://tttkmbb.com/conversion/days-to-weeks.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)