Time Unit Converter
Convert between milliseconds, seconds, minutes, hours, days, weeks, months and years instantly. This free time converter runs entirely in your browser — nothing is uploaded anywhere.
How to use the time converter
- Enter the amount of time. Type a number into the Value box — for example 90 for 90 minutes or 2.5 for two and a half hours.
- Select the units. Choose your starting unit in the From menu and your target unit in the To menu, or press ⇄ to swap them.
- Read the answer. The converted duration appears immediately, and the table below lists the same duration in every unit at once.
About this tool
Whether you are working out how many seconds are in a day, converting a video's runtime from minutes to hours, sizing a timeout in milliseconds, or estimating how many weeks are in a year, this converter handles it in one step. It spans a huge range — from nanoseconds and microseconds used in computing and physics up to days, weeks, months and years used in project planning and everyday life — so a single tool covers scientific, programming and calendar needs.
For the larger units, this converter uses standard average lengths: a month is treated as 30.44 days (one twelfth of an average year) and a year as 365.25 days, which accounts for leap years. These averages are ideal for general estimates and duration math. If you need the exact number of days between two specific calendar dates, use a date-difference calculator instead, since real months vary from 28 to 31 days. All conversions run locally in your browser, so your data stays completely private.
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 has 604,800 seconds, and an average year of 365.25 days has 31,557,600 seconds.
How long is a "month" in this converter?
A month is treated as 30.44 days — one twelfth of an average 365.25-day year. This average is best for rough duration math; real calendar months range from 28 to 31 days.
Why is a year 365.25 days instead of 365?
The extra quarter-day accounts for leap years, which add one day every four years. Using 365.25 days gives more accurate results when converting large spans of time into years.
Can I convert milliseconds for programming timeouts?
Yes. Choose milliseconds (or microseconds and nanoseconds for finer precision) as your unit. For example, 1,500 milliseconds converts to 1.5 seconds, which is handy when setting delays and timers in code.