How many seconds are in a day?

There are 86,400 seconds in a day: 24 hours × 60 minutes × 60 seconds.

How is a month defined in this converter?

As the average Gregorian month: 30.44 days (365.2425 days ÷ 12). Individual calendar months vary from 28 to 31 days.

Time Unit Converter

Convert durations between time units — from milliseconds all the way up to years. Handy for programmers converting timeouts, project planners estimating durations, or anyone curious how many seconds are in a year. Month and year conversions use average calendar lengths (30.44 days and 365.24 days).

Converters

Value

From

1 Seconds = 1,000 Milliseconds

1 Seconds (s) converted to all units
Unit	Value
Seconds (s)	1
Milliseconds (ms)	1,000
Minutes (min)	0.01666666667
Hours (h)	0.0002777777778
Days	0.00001157407407
Weeks	0.000001653439153
Months (avg)	0.0000003802648621
Years (avg)	0.00000003168873851

Private by default

This tool runs entirely in your browser. Your data is never uploaded to a server.

How it works

Which second, month, and year the converter uses

1 min = 60 s · 1 h = 3,600 s · 1 day = 86,400 s · 1 week = 604,800 s

Everything up to a week is exact, because those units are fixed multiples of the SI second. Months and years are not: their length depends on the calendar, so the converter uses the average Gregorian month and year — the only choice that stays consistent when you convert back.

1 average year = 365.2425 days = 31,556,952 seconds, the mean Gregorian year including the 400-year leap rule.
1 average month = 365.2425 ÷ 12 = 30.436875 days = 2,629,746 seconds.
Leap seconds are not modelled: a day is always 86,400 seconds here, exactly as it is in Unix time.
For a span between two real dates, use the Date Difference Calculator instead — an average year cannot tell you whether February had 28 days or 29.

For reference

Common time conversions

Duration	Seconds	Days
1 minute	60	0.000694
1 hour	3,600	0.0417
1 day	86,400	1
1 week	604,800	7
30 days	2,592,000	30
1 average month	2,629,746	30.436875
365 days	31,536,000	365
1 average year	31,556,952	365.2425

The two pairs show why the average matters: a flat 365-day year is 20,952 seconds — about 5 hours 49 minutes — short of the calendar average.

How to use

3 clear steps.

Enter a duration value.
Choose its unit (e.g. hours).
Choose the target unit (e.g. minutes) and read the converted duration.

Good to know

Frequently asked questions

How many seconds are in a day?: There are 86,400 seconds in a day: 24 hours × 60 minutes × 60 seconds.
How is a month defined in this converter?: As the average Gregorian month: 30.44 days (365.2425 days ÷ 12). Individual calendar months vary from 28 to 31 days.