Daylight Duration

Find the number of daylight hours between sunrise and sunset using decimal time on a 24-hour clock—perfect for photographers, gardeners, and travel planners.

Enter sunrise in decimal hours (e.g., 6.5 = 6:30 a.m.). Convert minutes by dividing by 60.
Sunset must be later than sunrise on the same day. For times after midnight, add 24 before subtracting.

Calculations assume a flat horizon and neglect atmospheric refraction, elevation, and weather effects. Use certified ephemeris data for navigation, aviation, or regulatory reporting.

Examples

  • Sunrise 6.25, Sunset 19.90 ⇒ 13.65 daylight hours
  • Sunrise 7.50, Sunset 20.25 ⇒ 12.75 daylight hours
  • Sunrise 5.25, Sunset 19.75 ⇒ 14.50 daylight hours
  • Sunrise 6.00, Sunset 17.30 ⇒ 11.30 daylight hours

FAQ

What time format should I use?

Use decimal hours on a 24-hour scale. For instance, 7:30 a.m. = 7.5 and 6:45 p.m. = 18.75.

Can the calculator handle polar daylight when sunset occurs after midnight?

Yes. Add 24 to the sunset time before entering it (e.g., 00:45 becomes 24.75) so the difference remains positive.

How do I turn the decimal result back into hours and minutes?

Take the integer part as hours and multiply the decimal remainder by 60 to obtain minutes. 13.65 hours becomes 13 hours and 0.65 × 60 ≈ 39 minutes.

Where can I get accurate sunrise and sunset data?

Consult national meteorological services, astronomical almanacs, or APIs like NOAA Solar Calculator, Timeanddate.com, or Sunrise-Sunset.org for daily values.

Additional Information

  • Daylight duration = Sunset time − Sunrise time when both are expressed in decimal hours on a 24-hour clock.
  • To convert hh:mm into decimals, divide minutes by 60 (e.g., 18:45 → 18 + 45/60 = 18.75).
  • Locations with midnight sun or polar night may require adding 24 hours to the sunset value to capture overnight daylight.

Related calculators