Femtosecond is 1e-15 second units.
Femtoseconds to Milliseconds Converter — fs to ms
Convert Femtosecond (fs) to Millisecond (ms) using the exact conversion factor (1 femtosecond = 1e-12 millisecond). See the formula, worked examples, and conversion table.
Femtoseconds to Milliseconds 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.
Millisecond is 0.001 second units.
Result = input x 1e-15 / 0.001.
Months and years use the average Gregorian year.
Reserved above the conversion cards and below the converter.
About Converting Femtoseconds to Milliseconds
Femtosecond and Millisecond 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 millisecond is 0.001 second units.
Formula
milliseconds = femtoseconds × 1e-12
This factor comes from each unit's defined relationship to the category's base unit: 1 femtosecond equals 1e-15 base units, and 1 millisecond equals 0.001 base units, so dividing one by the other gives the direct femtosecond-to-millisecond factor of 1e-12.
Simple example
1 fs × 1e-12 = 1e-12 ms
1 femtosecond = 1e-12 milliseconds.
Real-world example
24 fs × 1e-12 = 2.4e-11 ms
24 femtoseconds = 2.4e-11 milliseconds.
Conversion table
| Femtosecond (fs) | Millisecond (ms) |
|---|---|
| 1 fs | 1e-12 ms |
| 7 fs | 7e-12 ms |
| 24 fs | 2.4e-11 ms |
| 30 fs | 3e-11 ms |
| 100 fs | 1e-10 ms |
| 365 fs | 3.65e-10 ms |
Reverse conversion: Millisecond to Femtosecond
1e-12 ms × 1e+12 = 1 fs
1e-12 milliseconds = 1 femtosecond.
femtoseconds = milliseconds × 1e+12
For a page dedicated to this direction, see Millisecond to Femtosecond.
Understanding the Femtosecond (fs)
Femtosecond is 1e-15 second units.
Understanding the Millisecond (ms)
Millisecond is 0.001 second units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many milliseconds are in 1 femtosecond?
1 femtosecond equals 1e-12 milliseconds, using the exact defined conversion factor rather than an estimate.
How do I convert femtosecond to millisecond?
Multiply the femtosecond value by 1e-12. The converter above does this instantly to whatever precision you set.
How do I convert millisecond back to femtosecond?
Use the reverse factor: 1 millisecond equals 1e+12 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 millisecond?
Millisecond (ms) is a unit of time.
Is the femtosecond to millisecond conversion exact?
Yes. Both femtosecond and millisecond are defined by fixed standards rather than physical artifacts, so the factor of 1e-12 used above is exact to as many digits as you choose to display.