Years to Seconds Converter

What this converter does

This turns a number of years into seconds. Like the other year conversions, it uses an average year, so the result is a close estimate. A single year works out to over 31 million seconds. Enter the years and the seconds come straight back.

How to use it

1. Enter Years. Type the number of years.

Press Calculate and the equivalent in seconds appears.

Where the figure comes from

The conversion multiplies by 31,557,600, the number of seconds in an average year. It builds up from the smaller units: an average year is 365.25 days, each day is 86,400 seconds, and 365.25 times 86,400 is 31,557,600. A flat 365-day year is 31,536,000 seconds, so the extra is the leap-year quarter day, which is 21,600 seconds, carried through.

The pi times ten million trick

Here is a favourite among scientists and engineers who need a year in seconds in a hurry. A year is very close to pi times ten million seconds. Pi times ten million is about 31,416,000, and a year is about 31,557,600, so the approximation is good to within half a percent. It is not exact, and it is a coincidence rather than anything deep, but it is easy to remember and accurate enough for back-of-the-envelope work, which is why it has stuck around. For anything precise, the full figure is the one to use.

An example

Take 1 year. Multiply by 31,557,600 and you get about 31.6 million seconds. Two years is roughly 63 million. Turned around, a billion seconds is just under 32 years, which is another way to feel how big a billion really is.

Questions people ask

How many seconds are in a year?

About 31,557,600 on an average year of 365.25 days. A common 365-day year is 31,536,000 seconds, and a leap year is 31,622,400.

Is a year really pi times ten million seconds?

Very nearly. Pi times ten million is about 31,416,000 seconds, within half a percent of a year. It is a handy approximation, though not exact.

Is the result exact?

No, it is an estimate based on an average year. For an exact figure between two real dates, use a date-to-date tool.

How do I go from seconds back to years?

Divide the seconds by 31,557,600, or use a seconds-to-years converter, which uses the same average year.

References

1. U.S. Naval Observatory, Astronomical Applications Department: Leap Years. https://aa.usno.navy.mil/faq/leap_years