How to convert years to days
To convert a measurement in years to days, multiply the value by 365.2425. The conversion factor comes from the relationship between both units and the second.
For example, to convert 5 yr to days: 5 × 365.2425 = 1,826.2125 d.
What is a year?
A year here is the average Gregorian year, equal to 365.2425 days (31,556,952 seconds), the value that keeps the calendar aligned with the seasons. The Gregorian calendar, introduced in 1582, uses an average year of 365.2425 days achieved through its leap-year rules, refining the older Julian year of 365.25 days.
Common uses of years include: Interest and investment calculations; Age and anniversary tracking; Warranty and contract periods; Astronomical and historical timelines.
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.
When you need to convert years to days
Age calculations, interest accrual, and long deadlines often need years expressed in days. Because calendar years vary with leap years, this converter uses the average Gregorian year of 365.2425 days.
Years to days worked examples
Here are some common values converted:
1 yr = 365.2425 d 5 yr = 1,826.2125 d 10 yr = 3,652.425 d 50 yr = 18,262.125 d 100 yr = 36,524.25 d
Frequently asked questions
How many days are in one year?
One year (yr) equals 365.2425 days (d). Multiply any value in years by 365.2425 to convert to days.
How do I convert years to days?
Multiply the value in years by 365.2425. For example, 5 yr × 365.2425 = 1,826.2125 d.
How do I convert days to years?
Multiply the value in days by 0.002737907007, or divide by 365.2425. Use the swap button on the converter above to reverse the direction.
Is the year to day 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 years to days?
The formula is: d = yr × 365.2425. This comes from the definition of both units relative to the second.