Time Converter
Convert centuries, decades, years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds and nanoseconds. Choose any two units to get an instant result, formula and conversion table.
Convert Time Instantly
Edit either value, select your units or use a popular shortcut.
1 h equals 60 min
Calendar-based units use average lengths; results are estimates, not exact date calculations.
Popular time conversions
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How to Use the Time Converter
This tool converts a duration from one unit to another. For example, 2 hours is 120 minutes and 3 weeks is 21 days. It does not change time zones or calculate an exact end date.
Enter a duration
Type a number in the From field, or edit the To field to convert the other way.
Select units
Choose from nanoseconds through centuries, then use Swap to reverse the units.
Read the result
See the conversion, formula, worked example and a table for your selected units.
Time Conversion Formula
The calculator uses seconds as its reference unit. Each time unit has a number of seconds. To convert, multiply by the source unit’s seconds and divide by the destination unit’s seconds.
General conversion formula
Converted value = Input × (seconds per source unit ÷ seconds per destination unit)
Example: Convert 3 hours to minutes
One hour is 60 minutes, so 3 × 60 = 180 minutes.
Example: Convert 2 weeks to days
One week contains 7 days, so 2 × 7 = 14 days.
Example for the currently selected units: 5 h × 60 = 300 min.
Months, years, decades and centuries: The calculator uses the mean Gregorian year of 365.2425 days and a mean month of one-twelfth of that year (30.436875 days). These are average durations, not exact calendar dates. Use a date-based calculator when you need the exact number of days between dates.
Time Conversion Table
This table updates to show common values in the two currently selected units. Small values can appear in scientific notation to prevent them from rounding to zero on screen.
| Hours (h) | Minutes (min) |
|---|---|
| 1 | 60 |
| 2 | 120 |
| 5 | 300 |
| 10 | 600 |
| 25 | 1,500 |
| 50 | 3,000 |
| 100 | 6,000 |
| 1000 | 60,000 |
When a month, year, decade or century is selected, the table follows the stated average-length model.
Time Units Explained
Seconds, minutes, hours, days and weeks have fixed lengths in this duration converter. Calendar units such as months and years vary in the real world, so their conversions to days, hours or seconds use an average.
Why aren’t months always 30 days?
Calendar months can contain 28, 29, 30 or 31 days. Using 30 days for every month would not be the same as using the average Gregorian month. Here, one average month is 30.436875 days and one average year is 365.2425 days.
Does a century always have exactly 36,524.25 days?
No. One average century in this calculator is 100 × 365.2425 = 36,524.25 days. The exact number of days in a particular calendar century depends on the leap years it contains and which dates are used.
Frequently Asked Questions
How many minutes are in an hour?
One hour has exactly 60 minutes. Two hours equals 120 minutes, and 2.5 hours equals 150 minutes.
How many seconds are in one day?
For a standard 24-hour duration, 1 day = 24 × 60 × 60 = 86,400 seconds. This tool is for durations, not the local clock changes that can occur with daylight saving time.
How many days are in a week?
One week is exactly seven days, or 604,800 seconds in this calculator.
How many months are in one year?
One calendar year has 12 months. For conversions involving days, hours and seconds, this calculator treats a month as one-twelfth of an average Gregorian year.
How many years are in a decade or century?
One decade contains 10 years and one century contains 100 years. Their conversions to shorter fixed-length units are based on average year length.
How many milliseconds are in one second?
One second equals exactly 1,000 milliseconds, 1,000,000 microseconds, or 1,000,000,000 nanoseconds.
Is a month always 30 days?
No. Real months can contain 28 to 31 days. This converter uses 30.436875 days per average month to provide a consistent numeric approximation.
Can I convert decimal hours to hours and minutes?
This calculator converts between numeric units. To display a value such as 2.5 hours as 2 hours and 30 minutes, use the separate decimal-hours converter linked below.
Does this tool calculate time zones or exact date differences?
No. It converts amounts of elapsed time; it does not compare clocks in different cities or calculate days between specific dates.
Why does my result use scientific notation?
Very small or large values can be easier to read as powers of ten. For example, 1 nanosecond equals 1 × 10⁻⁹ seconds.
Related Time Calculators
Time-unit conversion is different from displaying hours and minutes together. These existing tools handle that format separately.
Time Conversion References
The SI second is the reference for metric time units. Fixed conversions such as 60 seconds in a minute and 24 hours in a standard duration day are used directly. For months and years this tool uses the average Gregorian-year convention of 365.2425 days. For information about SI units, see the BIPM SI Brochure.
Accuracy note: This tool converts durations; it does not count real leap days, daylight-saving transitions or exact calendar periods. For exact date arithmetic, start and end dates are required.