## 1 century has **3,155,760,000 **seconds.

Most years have 31,536,000 seconds.

However, we also have to take into leap years.

A century has 100 years.

Leap year is every 4 years.

That means we have 25 leap years per century, dividing 100 by 4.

If it’s a leap year, then 1 year has 31,622,400 seconds.

Knowing this, we can do our calculation.

## Seconds in a century calculation

= 75 normal years (seconds) + 25 leap years (seconds)

= 75 * 31,536,000 + 25 * 31,622,400

= **3,155,760,000**

That’s almost 3.2 billion seconds.

### How do we know the number of seconds in a year?

But let’s also back up for a second because we simply told you the number of seconds in a year.

Let’s go through step-by-step how we got there:

– We know that 1 year has 365 days (366 days during leap year).

– We know that 1 day is 24 hours.

– 1 hour is 60 minutes.

– And we know that 1 minute is 60 seconds.

So if we multiply all that through, we have:

= 365 days per year x 24 hours per day x 60 minutes per hour x 60 seconds per minute

= 31,536,000 seconds per year

Of course, now that you know that there are 86,400 seconds per day, you can calculate how many seconds there are…

– per week

– per year (above)

…and virtually every other expanse of time.