Time Unit Converter

How many hours is 2,000 minutes? How many seconds in a year? This converter moves a duration between milliseconds, seconds, minutes, hours, days, weeks, months, years, decades and centuries, and shows all of them together. Months and years are averages (30.4375 and 365.25 days), because real ones vary, so treat those two as approximate.

How to use it

1. Enter the amount of time.
2. Pick the starting unit and the unit you want first.
3. Read the headline answer and the full table.
4. Swap units if you want to go the other way.

When it helps

• Turning a project estimate from hours into working days or weeks.
• Working out how many seconds or minutes a long span contains.
• Checking maths and science homework.
• Comparing durations quoted in different units.

Good to know

• For an exact number of days between two calendar dates, the Date Difference tool is the better choice, since it counts real months.
• A day is 86,400 seconds and a week is 168 hours; those two never change.
• Fractions are fine in the input, so 1.5 hours works.

How the conversion works

The tool converts everything to seconds, then to the unit you want. Minutes are 60 seconds, hours 3,600, days 86,400 and weeks 604,800. Months and years are where it gets interesting, because the calendar isn't regular. A mean month is 30.4375 days, which is a year of 365.25 days divided by twelve, and the tool uses those averages.

That means a result such as 2 months is shown as 60.875 days, which is a fair estimate but not the number of days between two real dates. For that, use a date difference tool, which counts the actual days in each month.

Worked example: how long is a million seconds?

Enter 1,000,000 seconds and choose days. You get 11.57 days, or about 11 days, 13 hours and 46 minutes. A billion seconds is about 31.7 years, which surprises many people: the gap between a million and a billion is the gap between under two weeks and most of a working life.

Another one: 10,000 hours, often quoted as the amount of practice needed for mastery, is about 417 days of non-stop practice, or around 5.7 years at 4 hours a day, every day.

When approximate is fine and when it isn't

For planning, such as how many weeks a project lasts, the averages are perfectly good. For legal and financial deadlines, such as a 90-day notice or a one-month contract, you need real calendar rules, and those vary between contracts. A "month" in a contract can mean thirty days or a calendar month, and the difference can matter.

Computing systems have their own concerns, such as leap seconds and time zones. If you're working with timestamps rather than durations, the Unix Timestamp Converter is a better fit.

Common durations at a glance

A day is 24 hours, 1,440 minutes or 86,400 seconds. A week is 168 hours. A normal year is 8,760 hours, and a leap year 8,784. A working year of 52 weeks at 40 hours is 2,080 hours, which is why hourly and yearly pay convert with that number.

Milliseconds matter in computing: a blink takes about 300 to 400 ms, a good web page loads in under 2,000 ms, and a network ping within a city may take 10 ms.

Questions