Hours to Days (h to d)

Formula

1 h = 0.0416667 d

days = hours × 0.04166666667 — reverse: hours = days × 24

The factor is derived from the SI definitions of both units (base unit: s) as listed in NIST SP 811; results on this page are shown to 6 significant figures, the API returns up to 12.

Worked examples

• 5 h = 0.208333 d
• 12.5 h = 0.520833 d
• 100 h = 4.16667 d

Hours to days conversion table

FAQ

How many days are in one hour?

1 h = 0.0416667 d. 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 days?

Multiply the value in hours by 0.04166666667: days = hours × 0.04166666667. For example, 5 h = 0.208333 d.

How do I convert days back to hours?

Multiply by the inverse factor 24 (hours = days × 24), or use the days-to-hours page.

Related conversions

• Days to hours (reverse)
• Time Converter — all time units in one tool
• Hours to Minutes
• Minutes to Hours
• Minutes to Seconds
• Seconds to Minutes
• Weeks to Days
• Days to Weeks
• Years (365 days) to Days
• Days to Years (365 days)

Machine access

• API: GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=h&to_unit=day
• MCP: server https://tttkmbb.com/mcp, tool convert_units with {"value":5,"from_unit":"h","to_unit":"day"}
• Markdown: https://tttkmbb.com/conversion/hours-to-days.md · JSON: https://tttkmbb.com/conversion/hours-to-days.json (add ?value= for a result) · Units: /api/v1/units?quantity=time
• OpenAPI operationId: convert_units. Freshness: static. Authentication: none.

Sources

• NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors (standard)
• BIPM – The International System of Units (SI Brochure, 9th edition) (standard)
• Wikipedia – Conversion of units (reference)