Days to Hours Converter
Convert days to hours — twenty-four to the day. Results update as you type; exact factors shown.
One day is 24 hours — see the exact factor, not a rounded rule of thumb.
How the days to hours converter works
Time converts through the second. Minutes, hours, days and weeks are exact multiples. A month is taken as the Gregorian average (30.436875 days) and a year as the Gregorian average (365.2425 days = 31,556,952 s); calendar months and leap years vary from these averages.
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common time conversions
| From | To | Units |
|---|---|---|
| 0.5 d | 12 h | days to hours |
| 1 d | 24 h | day to hours |
| 2 d | 48 h | days to hours |
| 3 d | 72 h | days to hours |
| 5 d | 120 h | days to hours |
| 7 d | 168 h | days to hours |
| 10 d | 240 h | days to hours |
| 14 d | 336 h | days to hours |
| 21 d | 504 h | days to hours |
| 30 d | 720 h | days to hours |
| 90 d | 2,160 h | days to hours |
| 365 d | 8,760 h | days to hours |
Units in this converter and their exact factors
| Unit | Symbol | One unit in seconds |
|---|---|---|
| millisecond | ms | 0.001 second |
| second | s | 1 second |
| minute | min | 60 second |
| hour | h | 3,600 second |
| day | d | 86,400 second |
| week | wk | 604,800 second |
| month (average, 30.4369 days) | mo | 2,629,746 second |
| year (365.2425 days) | yr | 31,556,952 second |
FAQFrequently asked questions about time conversion
How many hours in a week?
168.
How many hours in a year?
8,760 in a common year, 8,784 in a leap year.
Do daylight saving changes affect this?
Real clock days can be 23 or 25 hours when the clocks change, but this conversion uses the nominal 24-hour day.
How many working hours in a month?
About 160 for a 40-hour week, or 152 for a 38-hour one.
How many hours is 90 days?
2,160.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.