Femto (f)
The SI prefix femto (f): a factor of 10⁻¹⁵, which is one quadrillionth (10⁻¹⁵).
What is a femto unit?
- Symbol
- f
- Quantity
- SI Prefixes
- Unit system
- SI
- Definition
- The SI prefix femto (f): a factor of 10⁻¹⁵, which is one quadrillionth (10⁻¹⁵).
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
Used for femtoseconds in laser physics and femtometers (fermis) in nuclear physics, where a proton is about 1.7 fm across.
Femto in other si prefixes units
- 1 f = 1e-45 QQuetta
- 1 f = 1e-42 RRonna
- 1 f = 1e-39 YYotta
- 1 f = 1e-36 ZZetta
- 1 f = 1e-33 EExa
- 1 f = 1e-30 PPeta
- 1 f = 1e-27 TTera
- 1 f = 1e-24 GGiga
- 1 f = 1e-21 MMega
- 1 f = 1e-18 kKilo
- 1 f = 1e-17 hHecto
- 1 f = 1e-16 daDeca
- 1 f = 1e-14 dDeci
- 1 f = 1e-13 cCenti
- 1 f = 1e-12 mMilli
- 1 f = 1e-9 µMicro
- 1 f = 0.000001 nNano
- 1 f = 0.001 pPico
- 1 f = 1000 aAtto
- 1 f = 1000000 zZepto
- 1 f = 1000000000 yYocto
- 1 f = 1000000000000 rRonto
- 1 f = 1e+15 qQuecto
- 1 f = 1e-15 ×1Base unit (no prefix)
Femto quick reference
| Femto | Kilo | Milli | Quetta |
|---|---|---|---|
| 1 f | = 1e-18 k | = 1e-12 m | = 1e-45 Q |
| 10 f | = 1e-17 k | = 1e-11 m | = 1e-44 Q |
| 100 f | = 1e-16 k | = 1e-10 m | = 1e-43 Q |
| 1000 f | = 1e-15 k | = 1e-9 m | = 1e-42 Q |
Where the femto unit fits
The next smaller si prefixes unit is the atto unit (a). 1 f = 1000 a, and 1 a = 0.001 f.
The next larger si prefixes unit is the pico unit (p). 1 f = 0.001 p, and 1 p = 1000 f.
Frequently asked questions
- How many kilo units are in one femto unit?
- One femto unit = 1e-18 k (kilo units).
- How many milli units are in one femto unit?
- One femto unit = 1e-12 m (milli units).
- How many quetta units are in one femto unit?
- One femto unit = 1e-45 Q (quetta units).