Time Converter
Convert between any two second units in your browser — instant, accurate, and private.
Example
1 ns = 0.001 µs. Switch the unit menus to convert between any pair.
How it works
Every value is converted through a single second base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting between time units is something you do constantly without thinking about it: estimating how many hours a multi-day project really has, working out a sleep schedule in minutes, reading sensor or API latencies in milliseconds and microseconds, or translating a subscription billed "per month" into days for a pro-rated refund. Because the time units here span fourteen orders of magnitude — from the nanosecond used in CPU timing to the year used in finance and planning — having one tool that walks every value through a single base unit removes the mental arithmetic and the chained-multiplication errors that creep in when you do it by hand.
Unlike most converters, time units are not a metric-versus-imperial split. The small units (nanosecond through millisecond) are SI decimal subdivisions of the second, the one base time unit in the International System, so each step is a clean factor of 1,000. The larger units come from astronomy and calendars instead: 60 seconds to a minute and 60 minutes to an hour are inherited from ancient Babylonian base-60 counting, while the day, week, month, and year are tied to the Earth's rotation, a seven-day social convention, and the Earth's orbit around the Sun.
A few rules of thumb make conversions fast in your head: there are 86,400 seconds in a day, 3,600 in an hour, and a handy near-coincidence — the number of seconds in a year is almost exactly π × 10⁷ (about 31.5 million), accurate to under half a percent. For rough work, one week is just over 600,000 seconds, and a million seconds is about 11.6 days.
The precision caveat is the whole reason to be careful here: seconds, minutes, hours, days, and weeks are exact and fixed, but "month" and "year" are not. A calendar month ranges from 28 to 31 days, so this tool has to assume an average month (about 30.44 days) and an average year of 365.25 days to account for leap years. That means any result that passes through Month or Year is a deliberate approximation — fine for estimates, but never use it for contract dates, legal deadlines, or payroll, where you should count actual calendar days instead.
Frequently asked questions
What does the time converter do?
It converts between common second units instantly. Pick a unit to convert from and a unit to convert to, type a value, and the result updates live.
Which units does this converter support?
It includes 10 units: Nanosecond, Microsecond, Millisecond, Second, Minute, Hour, Day, Week, Month, Year.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many seconds are in a day?
There are exactly 86,400 seconds in a day (24 hours × 60 minutes × 60 seconds). An hour holds 3,600 seconds and a minute holds 60.
How many milliseconds are in a second?
There are 1,000 milliseconds in a second. Stepping further down, one second equals 1,000,000 microseconds and 1,000,000,000 nanoseconds, since each SI prefix is a factor of 1,000.
How many days are in a month for conversion?
There is no single exact answer because months range from 28 to 31 days. Converters typically use the average calendar month of about 30.44 days (365.25 days ÷ 12), so a month-based result is an approximation, not a fixed value.
How many hours are in a week?
A week has 168 hours (7 days × 24 hours). That is also 10,080 minutes or 604,800 seconds.
How many seconds are in a year?
An average year of 365.25 days has about 31,557,600 seconds, while a common 365-day year has 31,536,000 seconds. A useful mnemonic is that a year is roughly π × 10⁷ (about 31.5 million) seconds.
What is the difference between a nanosecond, microsecond, and millisecond?
Each is 1,000 times larger than the one before it: a nanosecond is one billionth of a second, a microsecond is one millionth, and a millisecond is one thousandth. So 1 millisecond = 1,000 microseconds = 1,000,000 nanoseconds.
How many minutes are in a day?
There are 1,440 minutes in a day (24 hours × 60 minutes). That also equals 86,400 seconds.
Why isn't a year exactly 365 days in this converter?
Earth's orbit takes about 365.2425 days, so calendars add a leap day roughly every four years. Converters use an average of 365.25 days per year so long-span conversions stay accurate on average, even though no individual calendar year has that fractional length.
Related calculators