Convert days to years

One day equals 0.002738 years. To convert any number of days to years, multiply by 0.00273785.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Time conversions are exact down to the day and approximate above it. Seconds, minutes, hours and days have fixed ratios, but a month has no fixed length and a year has two — 365 days in the calendar and 365.25 in the astronomical convention used here. For anything with legal or contractual weight, count the actual calendar dates rather than converting a duration, because the difference accumulates precisely where it is least welcome.

days to years formula

To go the other way, use day = year ÷ 0.00273785.

About these units

A day is exactly 86,400 seconds by convention, though the Earth’s actual rotation drifts slightly against it — the discrepancy leap seconds were introduced to absorb.

This uses the Julian year of 365.25 days, the astronomical convention. A calendar year is 365 or 366 days depending on leap years.

Day is also written days. Year is also written years and yrs.

Sources

1. International Astronomical Union, Resolution B2 (2012), XXVIII General Assembly — the astronomical unit as exactly 149,597,870,700 m, and the Julian year of 365.25 days from which the light year and parsec follow.