Project managers convert between time units when planning schedules. A project estimated at 1,200 hours needs to be expressed in weeks for a Gantt chart. At 40 hours per week, that is 30 weeks, or roughly 7 months. The tool handles this conversion instantly.
Scientists and engineers convert between seconds and larger units for calculations. A satellite orbit of 5,400 seconds is 1.5 hours. A chemical reaction lasting 0.003 seconds is 3 milliseconds. The tool converts any value across all time units simultaneously.
Developers convert between milliseconds, seconds, and hours when working with timeouts and intervals. A session timeout of 3,600,000 milliseconds is 1 hour. A cache TTL of 86,400 seconds is 1 day. The tool shows all equivalent values at once.
HR professionals convert work hours to days for leave calculations. An employee with 120 hours of accrued vacation has 15 days off (at 8 hours per day). The tool converts 120 hours to 5 days instantly, though the 8-hour workday assumption must be applied separately.
Students convert between time units for physics and math homework. A problem asking how many seconds are in a 365-day year gets the answer 31,536,000 seconds. The tool provides this and all other unit equivalents in one view.
The calculator uses seconds as the base unit for all conversions. Each time unit has a defined number of seconds: 1 minute is 60 seconds, 1 hour is 3,600 seconds, 1 day is 86,400 seconds, 1 week is 604,800 seconds, 1 month is 2,629,746 seconds (the average month length), and 1 year is 31,556,952 seconds (the Julian year of 365.25 days).
To convert from one unit to another, the tool first multiplies the input value by the source unit's base value in seconds, then divides by the target unit's base value. For example, converting 2 hours to minutes: 2 times 3,600 equals 7,200 seconds, divided by 60 equals 120 minutes.
The month and year values are averages. A month is defined as one-twelfth of a Julian year (365.25 divided by 12 equals 30.4375 days, or 2,629,746 seconds). A year is defined as a Julian year of 365.25 days, which accounts for leap years by averaging the extra day over four years. Individual calendar months vary from 28 to 31 days, and calendar years are 365 or 366 days.
The All Conversions panel shows the input value converted to every supported unit simultaneously, so you can see the equivalent in seconds, minutes, hours, days, weeks, months, and years at a glance.
Input
1 hour to seconds
Output
3,600 seconds
The most common time unit conversion in programming
Input
1 day to hours
Output
24 hours
Standard day length. 1 day = 86,400 seconds.
Input
1 week to minutes
Output
10,080 minutes
7 days times 24 hours times 60 minutes
Input
1 year to seconds
Output
31,556,952 seconds
Julian year (365.25 days). Calendar years are 31,536,000 (common) or 31,622,400 (leap).
Input
100,000 seconds to hours
Output
27.78 hours
Roughly 1 day and 3.78 hours
Input
2.5 weeks to days
Output
17.5 days
2 weeks is 14 days, plus 0.5 week is 3.5 days
Things to watch out for
How many seconds are in a day?
There are 86,400 seconds in a standard day (24 hours times 60 minutes times 60 seconds). This is exact for calendar days. Days with leap seconds (which have been added roughly once every 18 months since 1972) have 86,401 seconds, but the tool uses the standard 86,400.
How many hours are in a week?
There are 168 hours in a week (7 days times 24 hours). This is exact and does not vary. The calculator handles this and all other time unit conversions using precise conversion factors.
How is a month defined in time conversions?
The calculator uses the average month length of 2,629,746 seconds (approximately 30.44 days). This is derived by dividing a Julian year (365.25 days) by 12. Individual calendar months vary from 28 to 31 days, so for exact calendar month calculations, use the Date Calculator instead.
What is a Julian year?
A Julian year is exactly 365.25 days or 31,556,952 seconds. It accounts for leap years by averaging the extra day over a 4-year cycle. This is the standard used in astronomy and scientific time calculations. Calendar years are 365 days (common) or 366 days (leap), but the Julian year provides a consistent average.
Why does the tool show exponential notation for some values?
For very large values (above 1,000,000) or very small values (below 0.001), exponential notation is more readable than long strings of digits. For example, 1,000,000 seconds is shown as 1.00e+6 in some units. The value is still precise, just displayed in a compact format.
Can I convert between any two time units?
Yes. The tool supports conversion between any pair of the seven supported units: seconds, minutes, hours, days, weeks, months, and years. Select the source unit, target unit, and enter a value. The result appears instantly, and all other unit equivalents are shown in the All Conversions panel.
Are the conversions exact?
Conversions between seconds, minutes, hours, days, and weeks are exact because these units have fixed relationships (60 seconds per minute, 24 hours per day, 7 days per week). Conversions involving months and years use average values and are therefore approximate for specific calendar periods.
Conversions between seconds, minutes, hours, days, and weeks are exact. Conversions involving months and years use average values (Julian year of 365.25 days, average month of 30.44 days) and are approximate for specific calendar periods. Leap seconds are not accounted for.