How to convert days to hours
To convert a measurement in days to hours, multiply the value by 24. The conversion factor comes from the relationship between both units and the second.
For example, to convert 5 d to hours: 5 × 24 = 120 h.
What is a day?
A day is a unit of time equal to 24 hours or 86,400 seconds, based on one full rotation of the Earth on its axis. The day is humanity's oldest natural time unit, set by the cycle of light and dark. The exact 86,400-second day is a civil convention; the true solar day varies slightly through the year.
Common uses of days include: Calendars and daily scheduling; Project timelines and deadlines; Shipping and delivery estimates; Medication dosing intervals.
What is a hour?
An hour is a unit of time equal to 60 minutes or 3,600 seconds. There are 24 hours in a day. The hour originated in ancient Egypt, where day and night were each divided into 12 parts. The fixed 60-minute hour became standard only after mechanical clocks made equal hours practical.
Common uses of hours include: Work shifts and hourly wages; Travel and flight durations; TV schedules and event planning; Battery life and runtime ratings.
When you need to convert days to hours
Project planning, hourly staffing, and travel estimates frequently move between days and hours. Knowing that a day holds 24 hours lets you translate a multi-day estimate into billable or working hours.
Days to hours worked examples
Here are some common values converted:
1 d = 24 h 5 d = 120 h 10 d = 240 h 50 d = 1,200 h 100 d = 2,400 h
Frequently asked questions
How many hours are in one day?
One day (d) equals 24 hours (h). Multiply any value in days by 24 to convert to hours.
How do I convert days to hours?
Multiply the value in days by 24. For example, 5 d × 24 = 120 h.
How do I convert hours to days?
Multiply the value in hours by 0.041666666667, or divide by 24. Use the swap button on the converter above to reverse the direction.
Is the day to hour conversion exact?
Fixed units (second through week) are exact. Month and year use the average Gregorian calendar length (30.44 and 365.2425 days) since these vary in practice.
What is the formula for days to hours?
The formula is: h = d × 24. This comes from the definition of both units relative to the second.