Time Converter
Convert time between seconds, minutes, hours, days, weeks, months and years, with a clear table of every converted value.
Time Converter — input your values
What does this conversion calculator do?
The time converter translates any duration between milliseconds, seconds, minutes, hours, days, weeks, months, years, decades and centuries. It is handy for scheduling, billing, science homework and long-term planning.
Because months and years have variable lengths, the converter uses standard reference values: a month of 30.44 days (one twelfth of a 365.25-day year) and a year of 365.25 days (the Julian year used in astronomy and finance).
Formula and variables
Month = 30.44 days (365.25 ÷ 12) and year = 365.25 days (Julian year). Calendar months vary from 28 to 31 days.
| Symbol | Meaning |
|---|---|
| factor(from) | How many seconds one 'from' unit equals |
| factor(to) | How many seconds one 'to' unit equals |
Worked example
Convert 2 days into hours.
- 1 day = 24 hours, so 2 days = 2 × 24 = 48 hours.
Answer: 2 days = 48 hours.
Tips and common mistakes
Tips
- Quick anchors: 1 day = 24 h, 1 week = 168 h, and 1 year ≈ 8,766 h.
- For payroll and billing, remember there are 2,080 working hours in a typical 52-week year at 40 h/week.
- When precision matters, use days or seconds instead of months — calendar months vary between 28 and 31 days.
- The Julian year (365.25 days) is standard in astronomy and finance; the Gregorian average is 365.2425 days.
Common mistakes to avoid
- Assuming every month has 30 days when calculating durations across calendar months.
- Forgetting leap years when converting years to days — the Julian year of 365.25 days already averages them in.
- Confusing milliseconds with seconds in latency and performance measurements — 100 ms is not 100 s.
Time Converter — frequently asked questions
How many seconds are in an hour?
3,600 seconds. An hour is 60 minutes and each minute is 60 seconds.
How many hours are in a year?
Using the 365.25-day year, one year is 8,766 hours, or 525,960 minutes.
How many weeks are in a year?
There are 52 weeks plus one day in a common year (52.18 weeks on average).
Why is a month 30.44 days in this converter?
Calendar months range from 28 to 31 days, so a fixed reference of 365.25 ÷ 12 = 30.44 days is used for calculations that need a consistent month.
How many milliseconds are in a second?
Exactly 1,000. A millisecond is one thousandth of a second.
What is a century in years?
A century is 100 years, which is 36,525 days in Julian years, or about 3,153,600,000 seconds.