The second is the SI base unit of time, defined by 9,192,631,770 oscillations of a caesium-133 atom. Everything from milliseconds in computing to years in finance is built from it.
How to use the Seconds 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 “Seconds to Milliseconds 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
Every time unit is defined by an exact factor relative to the second (the base unit). The calculator first turns the value you type into seconds, then turns that into the unit you picked in the “To” menu and into each of the common units below it. This two-step method means any unit can be converted to any other – 14 units are available in each menu – and you can type into any field, including a result, to work in the other direction. Changing a unit menu keeps the quantity the same and just re-expresses it, and the page heading and copied results follow your choice.
How to convert time units
- Choose the unit you have in the From menu and type the value, for example 3,600 s.
- Choose the unit you want in the To menu, for example milliseconds. The page heading changes to “Seconds to Milliseconds Converter”.
- The calculator multiplies by the second factor of the “from” unit and divides by the factor of the “to” unit: 3,600 s × 1 ÷ 0.001 = 3,600,000 ms.
1 second in common units
| Unit | Value |
|---|---|
| Milliseconds (ms) | 1,000 |
| Minutes (min) | 0.016666667 |
| Hours (h) | 0.00027777778 |
| Days (day) | 1.157407 × 10-5 |
| Weeks (week) | 1.653439 × 10-6 |
| Years (year) | 3.168874 × 10-8 |
Seconds conversion table
| Seconds | ms | min | h | day |
|---|---|---|---|---|
| 1 | 1,000 | 0.016666667 | 0.00027777778 | 1.157407 × 10-5 |
| 30 | 30,000 | 0.5 | 0.0083333333 | 0.00034722222 |
| 60 | 60,000 | 1 | 0.016666667 | 0.00069444444 |
| 90 | 90,000 | 1.5 | 0.025 | 0.0010416667 |
| 3,600 | 3,600,000 | 60 | 1 | 0.041666667 |
| 86,400 | 86,400,000 | 1,440 | 24 | 1 |
What is a second?
The second is the SI base unit of time, defined by 9,192,631,770 cycles of radiation from a caesium-133 atom.
What is a millisecond?
A millisecond is one thousandth of a second. Network latency, reaction times and computer timers are measured in milliseconds.
What is a minute?
A minute is 60 seconds. The base-60 split of hours and minutes comes from ancient Babylonian astronomy.
Common mistakes to avoid
Treating every month as 30 days or every year as 365 days in long calculations, and writing decimal hours such as 1.5 h as 1 h 50 min (it is 1 h 30 min).
Formula
1 s = 1,000 ms1 s = 0.016666667 min1 s = 0.00027777778 h1 s = 1.157407 × 10^-5 day1 s = 1.653439 × 10^-6 weekWorked example
Inputs — From: 3,600 s.
Results — To = 3,600,000 ms; Minutes = 60 min; Hours = 1 h; Days = 0.04166667 day; Weeks = 0.00595238 week; Years = 0.00011408 year; As h:mm:ss = 1:00:00.
Frequently asked questions
How many seconds in an hour?
3,600.
How many seconds in a year?
31,536,000 in a 365-day year; 31,556,952 on average.
How is the second defined?
By the caesium-133 hyperfine transition frequency.
How do I change the units?
Pick any unit in the From and To menus. The value is converted in place, and the heading changes to show your conversion, for example “Seconds to Milliseconds Converter”.
Can I type into any field?
Yes. Every field is editable, so you can start from whichever unit you have.
How many units can I convert between?
14 time units, from the everyday to the specialised.
Which units are exact?
All factors here are exact by definition except astronomical and similar reference values, which use internationally agreed constants.
What formula does the Seconds Converter use?
1 s = 1,000 ms.