Convert Days to Hours
Convert Days (d) to Hours (h) instantly and accurately.
Conversion Formula
h = d × 24
About Days
A day (d) = exactly 86,400 s. Earth's actual solar day varies ±16 s due to orbital eccentricity and axial tilt (equation of time). Leap seconds (abandoned in UTC after 2035) corrected the TAI-UT1 divergence. Mars's sol = 24 h 39 min 35 s ≈ 88,775 s; a Martian year = 668.6 sols. The day structures circadian biology, tides, and planetary science. 1 day = 86,400 s = 24 h.
About Hours
An hour (h) = exactly 3,600 s. The 24-hour day traces to ancient Egypt (10 daylight hours + 2 twilight + 12 night star-rise periods). Time zones are integer or half-hour UTC offsets (exceptions: India +5:30, Nepal +5:45). The kilowatt-hour = 3,600,000 J; Tc-99m half-life = 6.0067 h. Drug dosing and pharmacokinetics are expressed in hours. 1 h = 3,600 s = 60 min = 1/24 day.
Quick Reference Table
| Days (d) | Hours (h) |
|---|---|
| 1 d | 24 h |
| 2 d | 48 h |
| 5 d | 120 h |
| 10 d | 240 h |
| 25 d | 600 h |
| 50 d | 1200 h |
| 100 d | 2400 h |