The attosecond conversion selector on this page selects the time measurement unit to convert to starting from attoseconds (as). To make a conversion starting from a unit of time other than attosecond, simply click on the "Reset" button.
The attosecond is a unit of time in the metric system equal to one quintillionth of a second (1 as = 10-18 s).
One attosecond (as) is also equal to 0.001 femtoseconds (fs), or 10-9 nanoseconds (ns), or 10-12 microseconds (μs) or 10-15 milliseconds (ms), which are SI units of time.
The attosecond is the shortest unit of time that can be directly measured. Times of this magnitude (i.e., on the attosecond time scale) are used in science for atomic physics calculations. The atomic unit of time is equal to 2.418884326505(16) × 10-17 seconds or 24.18884326505(16) attoseconds.