How many seconds are in a day?

86,400 seconds: 24 hours of 60 minutes of 60 seconds. Occasional leap seconds are added to UTC to keep clocks aligned with the Earth's rotation, but they are rare and not included here.

How many days are in a month?

Calendar months run from 28 to 31 days. For conversion purposes this tool uses the average of 30.436875 days, which is one twelfth of the average Gregorian year. Use actual calendar dates if you need exact scheduling.

Why is a year 365.2425 days rather than 365?

The Earth's orbit takes slightly under 365.25 days. The Gregorian calendar adds a leap day every four years, skips it on century years, but restores it on centuries divisible by 400. Averaged out, that gives 365.2425 days per year.

How many hours are in a working year?

A full calendar year averages 8765.82 hours. A typical full-time working year is closer to 1800 to 2000 hours once weekends and leave are removed.

Time Converter - Seconds, Minutes, Hours, Days & Years

Time Converter Tool

Value

From

Result

Second (s)

How time units relate

Everything up to a week is exact: 60 seconds to a minute, 60 minutes to an hour, 24 hours to a day, 7 days to a week. Conversions in that range are simple multiplication and carry no ambiguity.

Months and years are the awkward ones, because calendar months vary from 28 to 31 days and years vary with leap days. This converter uses the average Gregorian year of 365.2425 days and defines a month as one twelfth of that, which is 30.436875 days. That is the right choice for rates, durations and projections. It is the wrong choice for calendar arithmetic: if you need to know the date 18 months from a specific day, count the actual months rather than multiplying.

The 365.2425 figure comes from the Gregorian leap rule: every fourth year is a leap year, except centuries, except centuries divisible by 400.

Quick reference

Common time conversions

Conversion	Result
1 minute	60 seconds
1 hour	3600 seconds
1 day	86,400 seconds
1 week	604,800 seconds
1 day	1440 minutes
1 week	168 hours
1 average month	30.436875 days
1 average year	365.2425 days
1 average year	8765.82 hours
1 second	1000 milliseconds

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Questions

Frequently Asked Questions

How many seconds are in a day?: 86,400 seconds: 24 hours of 60 minutes of 60 seconds. Occasional leap seconds are added to UTC to keep clocks aligned with the Earth's rotation, but they are rare and not included here.
How many days are in a month?: Calendar months run from 28 to 31 days. For conversion purposes this tool uses the average of 30.436875 days, which is one twelfth of the average Gregorian year. Use actual calendar dates if you need exact scheduling.
Why is a year 365.2425 days rather than 365?: The Earth's orbit takes slightly under 365.25 days. The Gregorian calendar adds a leap day every four years, skips it on century years, but restores it on centuries divisible by 400. Averaged out, that gives 365.2425 days per year.
How many hours are in a working year?: A full calendar year averages 8765.82 hours. A typical full-time working year is closer to 1800 to 2000 hours once weekends and leave are removed.