Second (s)
SI base unit of time, defined by the caesium-133 hyperfine transition frequency.
What is a second?
- Symbol
- s
- Quantity
- Time
- Unit system
- SI
- Definition
- SI base unit of time, defined by the caesium-133 hyperfine transition frequency.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
The SI base unit of time, used everywhere from stopwatches to physics.
Second in other time units
- 1 s = 1000000000 nsNanosecond
- 1 s = 1000000 µsMicrosecond
- 1 s = 1000 msSecond to Millisecond converter
- 1 s ≈ 0.01666666667 minSecond to Minute converter
- 1 s ≈ 0.0002777777778 hHour
- 1 s ≈ 0.00001157407407 dDay
- 1 s ≈ 0.000001653439153 wkWeek
- 1 s ≈ 3.168808781e-8 yrYear (Julian)
Second quick reference
| Second | Millisecond | Minute | Hour |
|---|---|---|---|
| 1 s | = 1000 ms | ≈ 0.01666666667 min | ≈ 0.0002777777778 h |
| 10 s | = 10000 ms | ≈ 0.1666666667 min | ≈ 0.002777777778 h |
| 100 s | = 100000 ms | ≈ 1.666666667 min | ≈ 0.02777777778 h |
| 1000 s | = 1000000 ms | ≈ 16.66666667 min | ≈ 0.2777777778 h |
Where the second fits
The next smaller time unit is the millisecond (ms). 1 s = 1000 ms, and 1 ms = 0.001 s.
The next larger time unit is the minute (min). 1 s ≈ 0.01666666667 min, and 1 min = 60 s.
Frequently asked questions
- How many milliseconds are in one second?
- One second = 1000 ms (milliseconds).
- How many minutes are in one second?
- One second ≈ 0.01666666667 min (minutes).
- How many hours are in one second?
- One second ≈ 0.0002777777778 h (hours).