Electrostatic Capacitance Converter

Electrostatic capacitance is the ability of a system to store electric charge in response to an applied voltage. Defined by the relation C = Q/V, where Q is stored charge and V is the voltage across the device, capacitance determines how much energy a capacitor can store (E = ½CV²) and how it behaves in AC circuits (impedance Z = 1/(jωC)). Capacitors are among the most ubiquitous electronic components, found in everything from the tiniest RF chip capacitors to the enormous supercapacitors used in regenerative braking systems. This converter supports 22 capacitance units spanning SI, CGS, and derived units.

The SI unit of capacitance is the farad (F), named after Michael Faraday. One farad is defined as the capacitance of a capacitor that stores one coulomb of charge when one volt is applied across it. One farad is an enormous capacitance in practice — a parallel-plate capacitor with 1 m² plates separated by 1 mm of air would have a capacitance of only about 8.85 nF (nanofarads). The full SI prefix range from the exafarad (EF = 10¹⁸ F) down to the attofarad (aF = 10⁻¹⁸ F) covers all known capacitance phenomena in nature and technology.

In everyday electronics, the most-used capacitance units are the microfarad (µF), nanofarad (nF), and picofarad (pF). Electrolytic capacitors in power supplies typically range from 10 µF to 10,000 µF. Film capacitors for timing and filtering applications span 1 nF to 10 µF. Ceramic capacitors for RF decoupling and high-frequency bypass range from 1 pF to 100 nF. The conversion chain is: 1 µF = 1000 nF = 1,000,000 pF. Memorising this chain eliminates errors when reading component markings and datasheets.

The millifarad (mF) is used for supercapacitors (also called ultracapacitors or electrochemical double-layer capacitors), which achieve capacitances from hundreds of millifarads to thousands of farads by exploiting ionic double-layer charge storage at electrode-electrolyte interfaces. Individual supercapacitor cells can hold 3000 F or more — genuine farad-range capacitors that blur the boundary between capacitors and batteries. These are used in automotive start-stop systems, UPS power backup, and burst-power delivery in industrial drives.

At the small end, the femtofarad (fF) and attofarad (aF) describe parasitic capacitances in semiconductor devices, MEMS sensors, and nanoscale structures. A gate oxide capacitance in a 5-nm CMOS transistor can be as small as a few femtofarads. Atomic force microscope probes interacting with surfaces through fringe fields create capacitances measured in attofarads. Accurate measurement and modelling of capacitances at this scale is crucial in semiconductor technology roadmap planning.

The coulomb/volt (C/V) unit is simply the definition of the farad expressed in base SI units, and is occasionally used in theoretical derivations and dimensional analysis to make the physical meaning explicit. The abfarad (CGS-EMU, = 10⁹ F) and statfarad (CGS-ESU, ≈ 1.113 × 10⁻¹² F) are legacy units from the pre-SI era. The statfarad is approximately 1.113 pF — usefully close to practical picofarad values — and appears in Gaussian-unit electrostatics calculations.

Capacitance conversions also arise in parasitic analysis of PCB traces. A 10 cm trace over a ground plane on a standard FR-4 PCB has a characteristic capacitance of about 1–3 pF per centimetre, or 10–30 pF total, which must be converted to impedance (Z = 1/ωC) for signal integrity analysis. Similarly, the input capacitance of an operational amplifier (typically 1–10 pF) interacts with feedback resistors to create poles in the closed-loop frequency response that affect bandwidth and stability.

This converter provides instant access to all 22 capacitance units: farad [F], exafarad [EF], petafarad [PF], terafarad [TF], gigafarad [GF], megafarad [MF], kilofarad [kF], hectofarad [hF], dekafarad [daF], decifarad [dF], centifarad [cF], millifarad [mF], microfarad [µF], nanofarad [nF], picofarad [pF], femtofarad [fF], attofarad [aF], coulomb/volt [C/V], abfarad [abF], EMU of capacitance, statfarad [stF], and ESU of capacitance. Select units, enter a value, and get your result instantly.