Time Converter
Convert a length of time into milliseconds, seconds, minutes, hours and days at once. You can also turn hours, minutes and seconds into seconds.
From hours, minutes and seconds to seconds
Enter hours, minutes and seconds to get the total in seconds, minutes and hours (decimal). Minutes and seconds must be 0 or more and less than 60.
Which tool should I use?
- Time Converter (this page): change the unit of one length of time, such as seconds to hours.
- Time Calculator: add and subtract lengths of time, or find the time between two clock times.
- Date Calculator: find the date a number of days, weeks, months or years away.
- Days Between Dates Calculator: count the days between two dates.
Time units and definitions
The size of each unit is listed below.
| Unit | Size of one unit | Definition and source |
|---|---|---|
| Seconds, minutes and hours | ||
| millisecond (ms) | 0.001 s | 1/1,000 of a second (SI prefix milli). NIST SP 811, Chapter 4 |
| second (s) | 1 s | The SI base unit of time. NIST SP 811, Chapter 4 |
| minute (min) | 60 s | 60 seconds. NIST SP 811, Chapter 5 |
| hour (h) | 3,600 s | 60 minutes = 3,600 seconds. NIST SP 811, Chapter 5 |
| Day | ||
| day (d) | 86,400 s | 24 hours = 86,400 seconds. This is not the actual length of a solar day. NIST SP 811, Chapter 5 |
The calculator first converts your time to seconds, then divides by the size of each unit. Calculations use exact fractions, and the only rounding is the one applied when a value is displayed. For the hours, minutes and seconds display, the seconds are rounded to 3 decimal places first, and then split into hours, minutes and seconds (59.9996 seconds is shown as 1 minute, not 60 seconds). Hours are not wrapped at 24, so 90,000 seconds is shown as 25:00:00.
Examples
- 3,661 seconds = 1 hour 1 minute 1 second (1:01:01)
- 1.5 hours = 90 minutes = 5,400 seconds
- 2 days = 48 hours = 2,880 minutes
- 1 hour 30 minutes 15.5 seconds = 5,415.5 seconds = about 1.504306 hours
- 1,500 milliseconds = 1.5 seconds
Notes
- You can enter decimals (up to 12 digits before the decimal point and 6 decimal places). Thousands separators such as 1,234.5 are accepted; use a period as the decimal separator.
- A "day" here means 24 hours (86,400 seconds). The time from one solar noon to the next changes with the seasons and the Earth's rotation, so it is not exactly this value.
- Weeks, months and years are not included because their lengths are not fixed in seconds. To count the days or the years, months and days between two dates, use the Days Between Dates Calculator.
Sources
The definitions on this page come from the sources below (checked on October 31, 2026). The NIST Guide lists the minute, hour and day as exact multiples of the second, and the SI prefix milli as 10⁻³.
- NIST Guide to the SI, Chapter 4: The Two Classes of SI Units and the SI Prefixes
- NIST Guide to the SI, Chapter 5: Units Outside the SI
Frequently asked questions
How many hours, minutes and seconds are 3,661 seconds?
1 hour 1 minute 1 second (1:01:01). 3,661 ÷ 3,600 = 1 remainder 61, and 61 seconds is 1 minute 1 second.
How many minutes are 1.5 hours?
90 minutes. Multiply hours by 60 to get minutes.
How do I convert minutes to hours?
Divide by 60. For example, 45 minutes is 0.75 hours. To get hours and minutes, read the "Hours, minutes and seconds" row in the result.
How many seconds are in a day?
86,400 seconds (24 hours).