Seconds, minutes and hours are exact multiples of each other, but months and years are not: this converter uses the average Gregorian month (30.436875 days) and year (365.2425 days), which is what you need for long periods and averages.
How to use the Time Unit Converter
- Pick the unit you are starting from in the From menu and type your value.
- Pick the unit you want in the To menu. The heading changes to match, for example “Hours to Seconds Converter”.
- The most common time units are shown below at the same time, so you can compare them at a glance.
- Type into any result to convert backwards, then use Copy results. The copied text starts with the heading for your chosen units.
Results update as you type. Everything is calculated in your browser.
How it works
Each of the 14 time units on this page is defined by an exact factor relative to the second, the base unit: 1 h = 3,600 s and 1 ms = 0.001 s, for example. The calculator first turns the value you type into seconds, then turns that into the unit you picked in the “To” menu and into milliseconds, minutes and days. Typing into any result works backwards the same way, so the hours and seconds values always describe the same amount.
How to convert time units
- Choose the unit you have in the From menu and type the value, for example 2.5 h.
- Choose the unit you want in the To menu, for example seconds. The page heading changes to “Hours to Seconds Converter”.
- The calculator multiplies by the second factor of the “from” unit and divides by the factor of the “to” unit: 2.5 h × 3,600 ÷ 1 = 9,000 s.
1 hour in common units
| Unit | Value |
|---|---|
| Seconds (s) | 3,600 |
| Milliseconds (ms) | 3,600,000 |
| Minutes (min) | 60 |
| Days (day) | 0.041666667 |
| Weeks (week) | 0.005952381 |
| Months (month) | 0.0013689535 |
| Years (year) | 0.00011407946 |
| Decades (decade) | 1.140795 × 10-5 |
Hours conversion table
| Hours | s | ms | min | day |
|---|---|---|---|---|
| 0.5 | 1,800 | 1,800,000 | 30 | 0.020833333 |
| 1 | 3,600 | 3,600,000 | 60 | 0.041666667 |
| 2 | 7,200 | 7,200,000 | 120 | 0.083333333 |
| 8 | 28,800 | 28,800,000 | 480 | 0.33333333 |
| 24 | 86,400 | 86,400,000 | 1,440 | 1 |
| 40 | 144,000 | 144,000,000 | 2,400 | 1.6666667 |
| 168 | 604,800 | 604,800,000 | 10,080 | 7 |
| 1,000 | 3,600,000 | 3.6 × 109 | 60,000 | 41.666667 |
Time units explained
- Hour (h)
- An hour is 60 minutes or 3,600 seconds. Wages, shifts and travel times are counted in hours.
- Second (s)
- The second is the SI base unit of time, defined by 9,192,631,770 cycles of radiation from a caesium-133 atom.
- Millisecond (ms)
- A millisecond is one thousandth of a second. Network latency, reaction times and computer timers are measured in milliseconds.
- Minute (min)
- A minute is 60 seconds. The base-60 split of hours and minutes comes from ancient Babylonian astronomy.
- Day (day)
- A day is 24 hours or 86,400 seconds. Calendar days occasionally differ by one second when a leap second is added.
- Week (week)
- A week is 7 days. Pregnancy, training plans and payroll cycles are often counted in weeks.
- Month (month)
- Calendar months have 28 to 31 days. For conversions, the average Gregorian month of 30.436875 days is used.
- Year (year)
- A calendar year has 365 or 366 days. The average Gregorian year, 365.2425 days, accounts for the leap-year rules.
- Decade (decade)
- A decade is 10 years.
Formula
1 h = 3,600 s
1 h = 3,600,000 ms
1 h = 60 min
1 h = 0.041666667 days
1 h = 0.005952381 weeks
Worked example
Inputs: From: 2.5 h.
Results: To = 9,000 s; Milliseconds = 9,000,000 ms; Minutes = 150 min; Days = 0.10416667 day; Weeks = 0.01488095 week; Months = 0.00342238 month; Years = 0.0002852 year.
Frequently asked questions
Why is a month 30.44 days?
That is the average month length over the 400-year Gregorian cycle.
How many hours in a year?
8,765.82 on average (8,760 in a 365-day year).
How many seconds are in one hour?
1 h = 3,600 s.
How many milliseconds are in one hour?
1 h = 3,600,000 ms.
How many minutes are in one hour?
1 h = 60 min.
Are these time conversions exact?
Yes. Every factor is an exact definition (for example 1 h = 3,600 s), so any difference you see is rounding in the last displayed digit.