Femtosecond is 1e-15 second units.
Femtoseconds to Attoseconds Converter — fs to as
Convert Femtosecond (fs) to Attosecond (as) using the exact conversion factor (1 femtosecond = 1,000 attosecond). See the formula, worked examples, and conversion table.
Femtoseconds to Attoseconds 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.
Attosecond is 1e-18 second units.
Result = input x 1e-15 / 1e-18.
Months and years use the average Gregorian year.
Reserved above the conversion cards and below the converter.
About Converting Femtoseconds to Attoseconds
Femtosecond and Attosecond 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. Specifically: Femtosecond is 1e-15 second units, and attosecond is 1e-18 second units.
Formula
attoseconds = femtoseconds × 1000
This factor comes from each unit's defined relationship to the category's base unit: 1 femtosecond equals 1e-15 base units, and 1 attosecond equals 1e-18 base units, so dividing one by the other gives the direct femtosecond-to-attosecond factor of 1000.
Simple example
1 fs × 1000 = 1,000 as
1 femtosecond = 1,000 attoseconds.
Real-world example
24 fs × 1000 = 24,000 as
24 femtoseconds = 24,000 attoseconds.
Conversion table
| Femtosecond (fs) | Attosecond (as) |
|---|---|
| 1 fs | 1,000 as |
| 7 fs | 7,000 as |
| 24 fs | 24,000 as |
| 30 fs | 30,000 as |
| 100 fs | 100,000 as |
| 365 fs | 365,000 as |
Reverse conversion: Attosecond to Femtosecond
1 as × 0.001 = 0.001 fs
1 attosecond = 0.001 femtoseconds.
femtoseconds = attoseconds × 0.001
For a page dedicated to this direction, see Attosecond to Femtosecond.
Understanding the Femtosecond (fs)
Femtosecond is 1e-15 second units.
Understanding the Attosecond (as)
Attosecond is 1e-18 second units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many attoseconds are in 1 femtosecond?
1 femtosecond equals 1,000 attoseconds, using the exact defined conversion factor rather than an estimate.
How do I convert femtosecond to attosecond?
Multiply the femtosecond value by 1000. The converter above does this instantly to whatever precision you set.
How do I convert attosecond back to femtosecond?
Use the reverse factor: 1 attosecond equals 0.001 femtoseconds. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtosecond?
Femtosecond (fs) is a unit of time.
What is a attosecond?
Attosecond (as) is a unit of time.
Is the femtosecond to attosecond conversion exact?
Yes. Both femtosecond and attosecond are defined by fixed standards rather than physical artifacts, so the factor of 1000 used above is exact to as many digits as you choose to display.