Years to Seconds
Convert years to seconds instantly — one year is 3.15576e+07 seconds.
| Years | Seconds |
|---|---|
| 1 yr | 31557600 s |
| 2 yr | 63115200 s |
| 3 yr | 94672800 s |
| 5 yr | 157788000 s |
| 10 yr | 315576000 s |
| 25 yr | 788940000 s |
| 50 yr | 1577880000 s |
| 100 yr | 3155760000 s |
How to use
- Enter a value in the Years field.
- The Seconds figure appears immediately — no button to press.
- Typing in the Seconds field converts back to Years the same way.
- Use the reference table for the values that come up most often.
Years to Seconds formula
The factor from years to seconds is 31557600.
s = yr × 31557600
Why this factor: the year and the second are both defined against the second, so dividing one definition by the other gives 31557600 directly. Both definitions are set out in full below.
To go the other way, divide by 31557600 — or use the Seconds to Years converter, which is the same calculation reversed.
Worked example
Given 15 yr, multiplying by 31557600 yields 473364000 s.
15 yr × 31557600 = 473364000 s
The converter above does this for any value you type, in either direction.
What is a year?
A year here means the Julian year, the fixed-length year used for scientific and financial arithmetic.
Definition: Exactly 365.25 days, so exactly 31,557,600 seconds.
Where it is used: Astronomy (the light-year is built on it), interest and depreciation calculations, and age arithmetic.
Worth knowing: The Gregorian calendar year averages 365.2425 days, so the two diverge by about 11 minutes per year.
What is a second?
The second is the SI base unit of time and the most precisely realized unit in all of measurement.
Definition: Defined by fixing the caesium-133 hyperfine transition frequency at exactly 9,192,631,770 hertz — the basis of every atomic clock.
Where it is used: Universal, and the reference for all other time units.
Years vs Seconds
The year is a specialized unit while the second is an SI unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many seconds are in a year?
One year equals 31557600 seconds.
What is the formula to convert years to seconds?
Multiply the number of years by 31557600. To reverse it, divide by 31557600 instead.
How do I convert seconds back to years?
Divide by 31557600, which is the same as multiplying by 3.16880878e-08.
How many seconds are in 10 years?
10 yr works out to 315576000 s.
Is there anything to watch out for with years?
The Gregorian calendar year averages 365.2425 days, so the two diverge by about 11 minutes per year.
How is the year defined?
Exactly 365.25 days, so exactly 31,557,600 seconds.