Time Converter
Convert between milliseconds, seconds, minutes, hours, days, weeks, months and years.
The time converter changes a duration from one unit to another. Use it for work hours, project planning, travel times, media durations and scientific data. Month and year use the average calendar values of 30.44 and 365.25 days.
How to use the converter
- Enter the duration.
- Choose the from and to units.
- Read the result and the full table of equivalents.
- Note that months and years here are averages, not exact calendar values.
How the conversion works
Result = value in seconds ÷ factor of the target unit
Worked example
2 hours to minutes
2 × 3,600 = 7,200 seconds ÷ 60 = 120 minutes
That is also 0.0833 days or 0.0048 months on average.
Popular conversions
Jump straight to a single conversion, or use the converter above for any pair.
Who should use this time converter
- Anyone working out hours for a timesheet or payroll, where total minutes must convert into decimal hours.
- Project and event planning, where a duration is given in one unit and needed in another.
- Students and researchers converting between seconds, hours and days for calculations or datasets.
- Media and production work, where clip lengths, runtime and encoding times are quoted inconsistently.
Common mistakes to avoid
- Mixing decimal hours with clock time. 1.5 hours is one hour and 30 minutes, not one hour and 50 minutes. In payroll, 7 hours 45 minutes is 7.75 hours — reading it as 7.45 understates the pay.
- Using 30-day months for exact arithmetic. Months run from 28 to 31 days. For real dates, count days rather than converting months into days.
- Assuming a year is exactly 365 days. The average is 365.25 days, and ignoring the quarter-day drift adds up to a full day every four years.
- Multiplying when you should divide. Larger units into smaller ones multiply, smaller into larger divide. It sounds obvious and is still the most frequent slip in manual conversions.
- Rounding at intermediate steps. Convert to seconds first, then to the target unit, and round only once at the end.
Decimal hours and clock time
Payroll and billing systems work in decimal hours while clocks work in sixty minutes. The conversion is straightforward once you see the pattern: divide the minutes by 60. Fifteen minutes is 0.25 hours, thirty is 0.5, forty-five is 0.75. So 7 hours 45 minutes becomes 7.75 hours and is billed at that rate.
It is also worth knowing the other averages used in time calculations. A calendar month averages about 30.44 days and a year about 365.25 days, which is where the leap year comes from. Converting a long duration between months and days therefore produces an approximation, which is why contracts, notices and deadlines are almost always written in days rather than months.
Time units explained
- Second
- The SI base unit of time, defined by the vibration of a caesium atom.
- Decimal hour
- An hour expressed as a decimal number. Used in timesheets and billing; 30 minutes is 0.5 hours.
- Julian year
- Exactly 365.25 days, the average used for scientific and financial calculations.
- Average month
- About 30.44 days, calculated by dividing a year by twelve.
- Leap year
- A year with an extra day in February, keeping calendar dates aligned with the Earth's orbit.
Splitting a duration into usable units
Many calculations become simple once a duration is expressed the way the task needs it. Ninety minutes is 1 hour 30 minutes in clock terms and 1.5 hours in decimal terms. A working year of 40-hour weeks is about 2,080 hours, or 260 working days before holidays. Ten thousand hours, often quoted as the time needed to master a skill, is roughly 417 days or 1.14 years of continuous practice.
The trap is mixing the two formats. A timesheet that reads 7.75 is seven hours and forty-five minutes, not seven hours and seventy-five minutes. Converting minutes to decimals by dividing by 60 is the single habit that prevents payroll and billing errors.
Frequently asked questions
How many seconds are in a day?
There are 86,400 seconds in a day: 24 hours × 60 minutes × 60 seconds. A week is 604,800 seconds.
How many hours are in a year?
A normal year has 8,760 hours; a leap year has 8,784. In working hours, a 40-hour week gives about 2,080 hours a year.
Why is a month shown as 30.44 days?
Because calendar months vary from 28 to 31 days, the average length over a year is about 30.44 days. For exact calendar dates, use our date difference calculator instead.