How many seconds are in an hour, day and week?

There are 3,600 seconds in an hour, 86,400 in a day and 604,800 in a week. These are exact, since each is built from the 60-second minute.

How long is a month in this converter?

A month is treated as the average month of 30.4375 days (365.25 ÷ 12), which equals 2,629,800 seconds. Real calendar months range from 28 to 31 days, so use a date-difference tool when exact dates matter.

Why is a year 365.25 days here and not 365?

The converter uses the Julian year of 365.25 days (31,557,600 seconds), the standard astronomical average that accounts for leap years. It is chosen so that exactly 12 average months equal one year.

What is the difference between a millisecond, microsecond and nanosecond?

A millisecond is one thousandth of a second, a microsecond is one millionth, and a nanosecond is one billionth. Each step down is 1,000 times smaller than the one above it.

How do I convert milliseconds to seconds?

Divide the milliseconds by 1,000. So 2,500 ms is 2.5 s. Select milliseconds as From and seconds as To and the converter does it for you.

Is my data sent anywhere?

No. Every conversion runs entirely in your browser with fixed factors. Nothing you type is uploaded or stored.

Time Unit Converter — Gera Tools

A time unit converter that moves cleanly between nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, months and years. Instead of a single two-field box, it shows your chosen From/To result and a live grid of the same amount expressed in every unit at once — handy whether you are reasoning about code latency in nanoseconds or planning a project in weeks and months.

How it works

Every unit is defined by how many seconds one of it contains, and the SI second is the baseline. When you type an amount, the tool first converts it to seconds, then divides that figure by the second-value of every other unit. That single pivot keeps the whole grid internally consistent: convert hours to seconds to days, and you get exactly the same answer as a direct hours-to-days division.

The small units are exact powers of ten: a millisecond is 0.001 s, a microsecond is 0.000001 s and a nanosecond is 0.000000001 s. The everyday units are exact too — a minute is 60 s, an hour is 3,600 s, a day is 86,400 s and a week is 604,800 s. Months and years are the only averages, because real calendars are irregular. This tool uses the average month of 30.4375 days (2,629,800 s) and the Julian year of 365.25 days (31,557,600 s), the conventional constants that make 12 months equal exactly one year. That choice is ideal for durations and estimates, but for exact calendar gaps between two specific dates you should use a dedicated date-difference calculator, since any given month might be 28, 29, 30 or 31 days long.

Precision is handled automatically. Very large or very small results — like nanoseconds in a year — switch to scientific notation so the figures stay readable, while everyday results are grouped and trimmed to a sensible number of significant digits. A swap button flips the From and To units in one click so you can check a conversion in both directions.

Worked example

Suppose you want to know how long 90 minutes is in other units. Enter 90, set From to minutes, and the tool converts: 90 min becomes 5,400 s, which is 1.5 hours, 0.0625 of a day, and about 0.0089 of a week. Flip it around with the swap button and 1.5 hours reads straight back as 90 minutes. The grid below the result shows all ten units together, so you can read off the milliseconds (5,400,000 ms) and the fraction of a month in the same glance.

Conversion reference

Unit	Symbol	In seconds
Nanosecond	ns	0.000000001
Microsecond	µs	0.000001
Millisecond	ms	0.001
Second	s	1
Minute	min	60
Hour	hr	3,600
Day	day	86,400
Week	week	604,800
Month (avg)	month	2,629,800
Year (Julian)	year	31,557,600

Every figure is calculated in your browser — no numbers are uploaded or stored.