Conversion from Year (yr) to Day (d) and vice versa

Here you can convert the Time unit Year into the unit Day and vice versa you can convert Day into Year. By clicking the "Swap units" icon, you will always obtain the desired conversion in the calculation result, i.e., yr to d or d to yr. With the following calculator you can also calculate any other Time unit.

Info about "Year"

A year (a) (Latin: annus) forms the time span of 365 days, or in the case of a leap year, 366 consecutive days. Due to its varying length, the year is not a physical unit of time and thus not a unit of time in the international SI system of units.

In the time unit converter, a year is always calculated to be 365 days.

In astronomical terms, a year is defined as the duration of the Earth’s orbit around the Sun, which lasts 365.25 days on average. Due to the quarter of a day, a normal calendar year (common year) is defined as 365 days, which is replaced every four years by a leap year with 366 days.

In everyday life, the term "year" is understood to mean the period from 1st January to 31st December.

Info about "Day"

Although the day (d) (Latin: dies) is not part of the International SI System of Units, it is indirectly approved for use with the SI through its definition that a day has 24 hours, and it is indirectly permitted for use with the SI. This is because the second form the official SI base value.

Therefore, 1 day equals 24 hours; 1440 minutes = 86,400 seconds 1 second equals 0.0000115741 days.

For thousands of years, the astronomical day (i.e., the time from sunrise to sunrise again) was the historical basic unit of time. The first reliable time measurements were made by the Egyptians in daylight using sundials, which they divided into 12 units according to their usual system of twelve numbers. At night, they used the position of the 12 stars to measure the time at night. It was not yet so important as days were longer in summer than in winter. Basically, the day and night were divided into twelve time periods. It was only 2,000 years ago that Greek astronomers divided the day into hours of equal length.

The day as the basis for time was not replaced by the second until the middle of the 20th century. With the use of modern quartz clocks, it was proven that the astronomical day (i.e., one revolution of the Earth) is constantly becoming somewhat slower. This confirmed the assumption that magma shifts beneath the earth's mantle and also the tides slow down the Earth's rotation. Therefore, since 1956, the second has been defined in such a way that it is measured by an atomic clock and a leap second must be added to the calendar year every 2 to 5 years. Hence, a day that is actually 86,400.003 atomic seconds long is always 86,400 seconds long, and from time to time, it has a one-off of 86,401 seconds.

Basis for conversion Year (yr) to Day (d)

The abbreviation for the "Time unit Year" is yr. The abbreviation for the "Time unit Day" is d.

Formula for the conversion of Year (yr) to Day (d)

The calculation from Year to Day shall be made using the following conversion formula:

Formula for the conversion of Day (d) to Year (yr)

The calculation from Day to Year shall be made using the following conversion formula:

Overview table: How many Year are how many Day?

Overview table: How many Day are how many Year?