How many seconds are in a year exactly?

It depends on the year. A common year (365 days) has 31,536,000 seconds. A leap year (366 days) has 31,622,400 seconds. The average Gregorian year is about 31,556,952 seconds.

Does a leap second change the number of seconds in a year?

Yes, but only by one second. When a leap second is added, that year has one extra second, so a common year would become 31,536,001 seconds and a leap year would become 31,622,401 seconds.

Why does a DST day have 23 or 25 hours?

Daylight saving time shifts clocks forward one hour in spring (losing an hour) and back one hour in fall (gaining an hour). That makes that local day 23 or 25 hours long, respectively.

How many minutes in a year if it is a leap year?

A leap year has 527,040 minutes. That is 1,440 minutes per day times 366 days.

How Many Seconds, Minutes and Hours in a Day, Week and Year

A day has 24 hours, 1,440 minutes and 86,400 seconds. A week has 168 hours, 10,080 minutes and 604,800 seconds. A common year packs 8,760 hours, 525,600 minutes and 31,536,000 seconds. A leap year stretches to 8,784 hours, 527,040 minutes and 31,622,400 seconds. The answer to how many seconds in a year depends on one thing: is it a leap year or a common year? Here are the exact figures for each calendar period, plus the exceptions that can trip you up.

The Basic Units Day and Week

Seconds in a Day

Every standard day has 24 hours. Take 24 hours, times 60 minutes per hour, and you get 1,440 minutes in a day. Times 60 seconds per minute gives 86,400 seconds. Those numbers are fixed.

A day that includes a daylight saving time change breaks the pattern. Clocks jump forward or back by one hour, so that local day runs 23 or 25 hours. The minutes and seconds shift by 60 minutes in that local day.

Seconds in a Week

A week contains 7 days. Take each daily figure and times it by 7. That gives 168 hours in a week, 10,080 minutes in a week, and 604,800 seconds in a week.

Common Year and Leap Year

Common Year

A common year has 365 days. To find how many hours in a year, take 24 hours times 365 days: 8,760 hours. For minutes, take 1,440 minutes times 365: 525,600 minutes. For seconds, take 86,400 seconds times 365: 31,536,000 seconds. That is how many seconds in a year for a common year.

Leap Year

A leap year has 366 days. Take 24 hours times 366 days: 8,784 hours. Take 1,440 minutes times 366: 527,040 minutes. Take 86,400 seconds times 366: 31,622,400 seconds. That is how many seconds in a year for a leap year.

The Average Gregorian Year

The Gregorian calendar, which most of the world uses, has a year length of 365.2425 days on average. This accounts for the regular pattern of leap years (every 4 years, except centuries not divisible by 400). The average Gregorian year works out to about 31,556,952 seconds. That figure is not a whole number of days; it is the average over a 400-year cycle.

For rough calculations, use the average year. It smooths out the leap-year pattern. For precise calendar work, check whether the specific year is common or leap.

Quick Reference Unit Conversions

Standard Conversion Table

Use these for planning, scheduling, or any calculation that requires exact figures.

Day: 24 hours, 1,440 minutes, 86,400 seconds
Week: 168 hours, 10,080 minutes, 604,800 seconds
Common year (365 days): 8,760 hours, 525,600 minutes, 31,536,000 seconds
Leap year (366 days): 8,784 hours, 527,040 minutes, 31,622,400 seconds
Average Gregorian year (365.2425 days): about 31,556,952 seconds

How to Convert Between Periods Yourself

Four-Step Method

If you need a value not listed above, calculate it yourself.

Start with the number of days in the period.
Times by 24 to get hours.
Times the hours by 60 to get minutes.
Times the minutes by 60 to get seconds.

Example: to find how many minutes in a day, take 24 hours times 60. You get 1,440 minutes. To find how many hours in a year for a common year, take 365 days times 24. You get 8,760 hours. The same method works for weeks: 7 days times 24 gives 168 hours, times 60 gives 10,080 minutes, times 60 gives 604,800 seconds.

Exceptions and Special Cases

Daylight Saving Time Days

In regions that observe DST, one day each spring has only 23 hours (the day clocks spring forward) and one day each fall has 25 hours (the day clocks fall back). On those days, the number of minutes and seconds changes. A 23-hour day has fewer minutes. A 25-hour day has more minutes. These are local clock times; the actual solar day remains 24 hours.

Leap Seconds

Occasionally, a leap second is added to Coordinated Universal Time (UTC) to keep atomic time in sync with Earth's rotation. When a leap second occurs, the minute that contains it has 61 seconds instead of 60. That minute still sits inside an hour of 60 minutes, but the extra second makes that particular day one second longer than 86,400. Leap seconds are not added on a fixed schedule; international timekeeping authorities announce them.

Using These Numbers in Practice

Knowing these conversions helps in everyday situations. Need seconds in a week? Use 604,800 seconds. Calculating annual totals for a project? Check whether the year is common or leap. For long-term averages, use the average Gregorian year figure of about 31,556,952 seconds.

Check the current date, week number, and day of year to determine which year type you are in. The numbers here give you the foundation for any time-based calculation.