The second is the SI base unit of time.
Seconds to Femtoseconds Converter — s to fs
Convert Seconds (s) to Femtosecond (fs) using the exact conversion factor (1 seconds = 1e+15 femtosecond). See the formula, worked examples, conversion table, history, and common uses.
Seconds to Femtoseconds converter
Converter
Time Converter
Convert SI time, civil time, historical durations, months, and years.
Context values
Some unit families need one extra value for a physically accurate result.
Femtosecond is 1e-15 second units.
Result = input x 1 / 1e-15.
Months and years use the average Gregorian year.
Reserved above the conversion cards and below the converter.
About Converting Seconds to Femtoseconds
Seconds and Femtosecond are both everyday units of duration, and converting between them is one of the most routine calculations there is — scheduling, project planning, and billing all depend on it. Seconds is most often used for fundamental unit for all timekeeping and scientific measurement.
Formula
femtoseconds = seconds × 1e+15
This factor comes from each unit's defined relationship to the category's base unit: 1 seconds equals 1 base unit, and 1 femtosecond equals 1e-15 base units, so dividing one by the other gives the direct seconds-to-femtosecond factor of 1e+15.
Simple example
1 s × 1e+15 = 1e+15 fs
1 seconds = 1e+15 femtoseconds.
Real-world example
24 s × 1e+15 = 2.4e+16 fs
24 seconds = 2.4e+16 femtoseconds.
Conversion table
| Seconds (s) | Femtosecond (fs) |
|---|---|
| 1 s | 1e+15 fs |
| 7 s | 7e+15 fs |
| 24 s | 2.4e+16 fs |
| 30 s | 3e+16 fs |
| 100 s | 1e+17 fs |
| 365 s | 3.65e+17 fs |
Reverse conversion: Femtosecond to Seconds
1e+15 fs × 1e-15 = 1 s
1e+15 femtoseconds = 1 seconds.
seconds = femtoseconds × 1e-15
For a page dedicated to this direction, see Femtosecond to Seconds.
Understanding the Seconds
Seconds (s) measures time. The second is the SI base unit of time, currently defined via a fixed number of cesium atomic transitions. It is classified as a SI base unit.
Where it's used: Universal
Uses of the Seconds today
- Fundamental unit for all timekeeping and scientific measurement
- Basis for derived units like speed (m/s) and frequency (Hz)
History of the Seconds
The second originated from dividing the day into 24 hours, each into 60 minutes, each into 60 seconds — a sexagesimal (base-60) system inherited from Babylonian astronomy. Since 1967, the second has been defined atomically, as exactly 9,192,631,770 periods of radiation from a cesium-133 transition, decoupling timekeeping from the Earth's slightly irregular rotation.
Historical origin. Seconds was not the invention of a single named person; it developed through the process described above.
Understanding the Femtosecond (fs)
Femtosecond is 1e-15 second units.
Seconds — sources
- BIPM — The second (SI base unit) — Current atomic definition and history of the second.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many femtoseconds are in 1 seconds?
1 seconds equals 1e+15 femtoseconds, using the exact defined conversion factor rather than an estimate.
How do I convert seconds to femtosecond?
Multiply the seconds value by 1e+15. The converter above does this instantly to whatever precision you set.
How do I convert femtosecond back to seconds?
Use the reverse factor: 1 femtosecond equals 1e-15 seconds. You can also use the swap control in the converter above to flip the direction instantly.
What is a seconds?
Seconds (s) measures time. The second is the SI base unit of time, currently defined via a fixed number of cesium atomic transitions. It is classified as a SI base unit.
What is a femtosecond?
Femtosecond (fs) is a unit of time.
Is the seconds to femtosecond conversion exact?
Yes. Both seconds and femtosecond are defined by fixed standards rather than physical artifacts, so the factor of 1e+15 used above is exact to as many digits as you choose to display.
Where is the seconds still used today?
Universal