Capacitance Converter Calculator

Capacitance Converter & RC Helper

Engineer‑grade capacitance conversions with bidirectional units, auto‑scaling, and human‑readable output. Server‑side only—no JavaScript. Batch normalize lists, compute series/parallel, reactance, RC constants, energy and charge. Snap to E‑series values, apply tolerance, build a mini‑BOM with CSV export, and generate shareable permalinks in a clean Bootstrap layout. Accessible, multilingual hints, keyboard friendly forms, dark‑mode ready, everywhere.

Capacitance converter

Value (you can type unit, e.g., 4.7uF, 220 nF)

From unit

To unit

Significant figures

Engineering notation

Converted

4700 nF

Auto-scale: 4.7 µF

Unit	Value
F	4.7E-6
mF	0.0047
µF	4.7
nF	4700
pF	4700000
fF	4700000000

Tips: Use u or µ for micro. Press the Convert button. Try 0.047 uF or 47000 pF.

Batch converter

Paste a list like: 100 nF, 4.7 uF, 1e-6 F. We’ll normalize to F, µF, nF, pF.

Series / Parallel equivalent

Equivalent: —

RC / Reactance tools

Reactance |X_c|

33.86 Ω

RC time constant τ

0.0047 s

Energy E

5.875E-5 J

Charge Q

2.35E-5 C

With ±10.00% tolerance: C∈[4.23E-6 F, 5.17E-6 F], |Xc|∈[30.78 Ω, 37.63 Ω], τ∈[0.00423 s, 0.00517 s]

E-series rounding

Nearest E12: 4.7 µF (4.7 µF), Δ = 0%

Mini-BOM

#	Capacitance	Normalized (µF)	Voltage	Package

Download CSV Clear

Shareable permalink

This URL encodes your current inputs. Copy it manually (no JavaScript used).

Quick reference tables

µF	nF	pF
0.001	1	1000
0.01	10	10000
0.022	22	22000
0.047	47	47000
0.1	100	100000
0.22	220	220000
0.47	470	470000
1	1000	1000000
2.2	2200	2200000
4.7	4700	4700000
10	10000	10000000
22	22000	22000000
47	47000	47000000
100	100000	100000000

τ (multiples)	% Charged
1 τ	63.2%
2 τ	86.5%
3 τ	95.0%
4 τ	98.2%
5 τ	99.3%
7 τ	≈ 100%

Formulas assume ideal capacitors; real parts exhibit ESR/ESL and voltage bias (MLCC). Add derating for high voltage or temperature.

How this Capacitance Converter Works (Formulas & Practical Notes)

This calculator is built to solve everyday capacitor tasks with accuracy and transparency, entirely on the server—no JavaScript required. At its core, it normalizes any input to farads and then renders human‑readable values across common prefixes. It also computes series/parallel equivalents, capacitive reactance, RC time constants, stored energy, charge, and tolerance ranges, and it snaps design targets to real‑world E‑series values for easier part selection.

Unit system and conversion

Capacitance (C) is measured in farads (F). To keep numbers readable, engineers usually work in submultiples. The calculator supports milifarads (mF), microfarads (µF or uF), nanofarads (nF), picofarads (pF), and femtofarads (fF). Internally, a value like “4.7uF” becomes 4.7 × 10⁻⁶ F. Conversions are proportional: C_target = C_F ÷ scale(target).

Unit	Symbol	Multiplier to F	Example → F
Farad	F	1	1 F → 1 F
Milifarad	mF	10⁻³	3.3 mF → 3.3×10⁻³ F
Microfarad	µF (uF)	10⁻⁶	4.7 µF → 4.7×10⁻⁶ F
Nanofarad	nF	10⁻⁹	220 nF → 2.2×10⁻⁷ F
Picofarad	pF	10⁻¹²	1000 pF → 1×10⁻⁹ F
Femtofarad	fF	10⁻¹⁵	500 fF → 5×10⁻¹³ F

Unit

Symbol

Multiplier to F

Example → F

Farad

1 F → 1 F

Milifarad

10⁻³

3.3 mF → 3.3×10⁻³ F

Microfarad

µF (uF)

10⁻⁶

4.7 µF → 4.7×10⁻⁶ F

Nanofarad

10⁻⁹

220 nF → 2.2×10⁻⁷ F

Picofarad

10⁻¹²

1000 pF → 1×10⁻⁹ F

Femtofarad

10⁻¹⁵

500 fF → 5×10⁻¹³ F

Series, parallel, and real‑world selection

Combining capacitors changes total capacitance. In parallel, capacitances add directly: C_eq = Σ C_i. In series, reciprocals add: 1/C_eq = Σ (1/C_i). Because real parts are sold in preferred values, the tool also snaps a target to the nearest E‑series (E6/E12/E24/E96). E‑series are logarithmic sets designed to cover each decade with roughly constant relative spacing, helping you select parts that are commonly stocked.

E12 row (one decade)
10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

E12 row (one decade)

10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

Reactance, RC timing, energy, and charge

A capacitor’s opposition to AC is its reactance, |X_c| = 1 / (2π f C) (ohms), which falls as frequency or capacitance increases. In an RC circuit, the time constant is τ = R·C. After one τ, a step charge reaches about 63.2% of its final value; after five τ, it is above 99%. Stored energy is E = ½ C V² (joules) and charge is Q = C·V (coulombs).

Example	Value
Given	C = 100 nF, f = 1 kHz, R = 1 kΩ, V = 5 V
Reactance	\|X_c\| ≈ 1 / (2π·1000·100×10⁻⁹) ≈ 1.59 kΩ
Time constant	τ = R·C = 1000·100×10⁻⁹ = 0.0001 s = 0.1 ms
Energy	E = ½·C·V² = 0.5·100×10⁻⁹·25 ≈ 1.25 µJ
Charge	Q = C·V = 100×10⁻⁹·5 = 0.5 µC

Example

Value

Given

C = 100 nF, f = 1 kHz, R = 1 kΩ, V = 5 V

Reactance

|X_c| ≈ 1 / (2π·1000·100×10⁻⁹) ≈ 1.59 kΩ

Time constant

τ = R·C = 1000·100×10⁻⁹ = 0.0001 s = 0.1 ms

Energy

E = ½·C·V² = 0.5·100×10⁻⁹·25 ≈ 1.25 µJ

Charge

Q = C·V = 100×10⁻⁹·5 = 0.5 µC

Tolerance, temperature, and voltage bias

Real capacitors vary. If tolerance is ±t%, then C_min = C(1−t) and C_max = C(1+t). Because reactance depends on C, your |X_c| and τ will vary accordingly; the calculator shows these ranges. Multilayer ceramic capacitors (MLCCs) can lose a significant fraction of their capacitance under DC bias, and some dielectrics (e.g., Y5V) shift with temperature. Use more stable dielectrics (e.g., C0G/NP0 or X7R), derate voltage, and validate at operating conditions whenever precision matters.

Good design hygiene

Choose values from the relevant E‑series, round thoughtfully, and include margin for tolerance, temperature, and aging. For filters, look at the full impedance versus frequency; for timing, sanity‑check τ against your clocking and interrupt budgets. Finally, ensure voltage ratings exceed worst‑case transients, and remember polarized electrolytics are not suitable for AC coupling unless they are back‑to‑back or specifically designed for bipolar operation.