Capacitance units — µF, nF and pF
Same physics, six orders of magnitude in practical values. Datasheets mix units on the same line — read the suffix carefully.
Capacitor values span from single picofarads (RF matching) to hundreds of thousands of microfarads (motor start caps). The prefixes are consistent SI, but datasheets and schematics blend them freely.
The exact factors
1 F = 10⁶ µF = 10⁹ nF = 10¹² pF > 1 µF = 1000 nF = 1 000 000 pF > 1 nF = 1000 pF
Where each dominates
pF (1–1000 pF): RF matching, crystal load caps, PCB parasitics, timing networks. nF (1–1000 nF): decoupling, filter caps, high-frequency bypass. µF (1–1000 µF): power supply bulk, motor run/start, audio coupling. mF/F: hold-up capacitors, supercapacitors.
Reading old markings
Ceramic caps: '104' = 10 × 10⁴ pF = 100 nF = 0.1 µF. '473' = 47 nF. '221' = 220 pF. Old European: '4n7' = 4.7 nF; '2µ2' = 2.2 µF. The letter replaces the decimal point.
Worked example — decoupling
Digital IC supply pin needs 100 nF close to the pin (high-frequency bypass) plus 10 µF nearby (mid-frequency reservoir) plus 100 µF at the regulator (bulk). All three cover different frequency decades — designing with a single capacitor value misses two orders of magnitude of impedance.
Recap
µF, nF, pF differ by 1000× steps. Marking codes hide behind two-digit + exponent format.
Try the converters mentioned in this article
FAQ
What is a 'farad'?+
The SI unit — 1 F = 1 C/V. Real capacitors are usually µF and smaller; supercaps hit hundreds of farads.
Why bother with pF-scale caps?+
At GHz frequencies, 1 pF has impedance ~50 Ω — significant for RF.
This article was written by The Turbo Unit Converter engineering desk (Applied metrology & engineering units) and last reviewed on 2026-07-07 against NIST SP 811 and the BIPM SI Brochure. Read our full editorial policy.