Skip to the calculator
Rule Calculator

Convert Days to Years

1 day is 0.002738 yr. One day is exactly 0.00273790700699 years.

One day is 0.002737907 years. To convert days to years, multiply by 0.002737907; to go the other way, divide by 0.002737907 or multiply by 365.2425. This one is an average rather than an exact factor: a calendar year is 365 days or 366, so this figure is an average across the 400-year leap cycle. The definition comes from BIPM SI Brochure. Exactly 86,400 seconds by convention.

Factor checked against the defining standard · How we check

Years
0.002738 yr
Days × 0.002737907
value * 0.002737907006990.003 yr

1 day in every time unit

UnitValueExact factor
seconds86,400 s× 86,400
minutes1,440 min× 1,440
hours24 h× 24
days (as entered)1 d
weeks0.1428571429 wk× 0.142857142857
months0.03285488408 mo× 0.0328548840839
years0.002737907007 yr× 0.00273790700699

Factors are entered by hand from BIPM SI Brochure rather than derived from a units library, so the ones that terminate are exact rather than rounded.

How do you convert days to years?

  1. 1.Take the measurement in days.
  2. 2.Multiply by 0.002737907 — that is how many years fit in one day.
  3. 3.To go back the other way, divide by 0.002737907, or multiply by 365.2425.

Days to years conversion table

DaysYears
1 d0.002738 yr
2 d0.005476 yr
3 d0.008214 yr
4 d0.010952 yr
5 d0.01369 yr
6 d0.016427 yr
7 d0.019165 yr
8 d0.021903 yr
9 d0.024641 yr
10 d0.027379 yr
12 d0.032855 yr
15 d0.041069 yr
20 d0.054758 yr
25 d0.068448 yr
50 d0.136895 yr
100 d0.273791 yr

What are days and years?

Day (d)
Exactly 86,400 seconds by convention. A solar day runs a few milliseconds long or short, which is what a leap second corrects.
Year (yr)
The average Gregorian year, 365.2425 days — the figure the leap-year rule exists to produce.

Source: BIPM SI Brochure — the second, and units accepted for use with the SI

Questions people actually ask

How many years are in a day?
0.002737907. The average Gregorian year, 365.2425 days — the figure the leap-year rule exists to produce.
How do I convert years back to days?
Divide by 0.002737907, or multiply by 365.2425 — they are the same operation.

Other time conversions

Years to days — the same conversion the other way.

Calculators that work in time