Free online time unit converter. Convert seconds to minutes, hours to days, days to weeks, minutes to milliseconds, weeks to months, and more — instant results, strong validation, and a visual comparison chart. Works on phone, tablet and desktop.
Nanoseconds • Seconds • Hours • Days • Years
Years use 365.25 days and months use the average 30.4375 days, so long-range conversions stay accurate rather than drifting.
See the scale difference at a glance — useful when converting between very small (ms) and very large (years) units.
Every conversion runs entirely in your browser — no server, no account, nothing sent anywhere.
Time conversion is one of the most common everyday calculations — figuring out how many minutes are in a workday, how many hours a project will take, how many seconds are in a year, or how many days until a deadline. While the relationships are fixed and simple (60 seconds in a minute, 60 minutes in an hour, 24 hours in a day), the larger units introduce subtleties: a calendar month varies from 28 to 31 days, and a year is not exactly 365 days because of leap years.
The fixed building blocks: 1 minute = 60 seconds. 1 hour = 60 minutes = 3,600 seconds. 1 day = 24 hours = 1,440 minutes = 86,400 seconds. 1 week = 7 days = 168 hours = 604,800 seconds. These never change. The averaged units: because months differ in length, this converter uses the average month of 30.4375 days (365.25 ÷ 12), and a year of 365.25 days to fold in the leap-year correction (one extra day every 4 years). That makes 1 year ≈ 31,557,600 seconds and 1 month ≈ 2,629,800 seconds.
Quick mental shortcuts: There are 86,400 seconds in a day and about 31.5 million seconds in a year (a handy approximation: π × 10⁷ ≈ 31.4 million is famously close). A 90-minute movie is 1.5 hours. A 40-hour work week is 2,400 minutes. There are roughly 8,760 hours in a year (365 × 24), or 8,766 hours using the 365.25-day year.
8-hour shift = 480 minutes = 28,800 seconds. 40-hour week = 2,400 minutes. Full-time year (2,080 hours) = 124,800 minutes. A 25-minute Pomodoro = 1,500 seconds.
1 day = 86,400 s. 1 week = 604,800 s. 1 month ≈ 2.63 million s. 1 year ≈ 31.56 million s. A 2-hour exam = 7,200 s. A 90-day quarter ≈ 2,160 hours.
1 second = 1,000 milliseconds = 1,000,000 microseconds = 1,000,000,000 nanoseconds. A camera shutter at 1/250 s = 4 ms. A 60 fps video frame lasts 16.7 ms.
1 decade = 10 years ≈ 3,652.5 days. 1 year ≈ 52.18 weeks. 1,000,000 seconds ≈ 11.57 days. 1 billion seconds ≈ 31.7 years — a "gigasecond" milestone many people quietly pass in their early 30s.
Time is the only base SI quantity whose everyday units are not decimal, and the reason is Babylonian: base-60 arithmetic gave us 60 seconds, 60 minutes and, doubled, 24 hours. The second itself is defined by caesium atomic transitions rather than by astronomy, because the Earth's rotation is neither constant nor perfectly regular. Above the day, units stop being exact: a month has no fixed length and a year is 365.2425 days under the Gregorian calendar, which is why converting "3 months" to days requires a convention rather than a calculation.
seconds = value × factor_from1 min = 60 s · 1 h = 3,600 s · 1 day = 86,400 s1 Gregorian year = 365.2425 days = 31,556,952 swhere:
Assumptions: Leap seconds have occasionally been inserted to keep clocks aligned with Earth's rotation; the practice is due to be discontinued by 2035. Calendar arithmetic across months should use date functions, not fixed second counts.
A conversion that makes the scale of large numbers concrete.
Result1 billion seconds = 31.69 years
The million/billion/trillion progression — 11.6 days, 31.7 years, 31,688 years — is the clearest demonstration that these words describe wildly different magnitudes despite sounding similar. The same ratio applies to sums of money.