Capacitor Code Calculator
Decode 3-digit ceramic and film capacitor codes to pF, nF and µF in one step. Includes a pF ↔ nF ↔ µF unit converter for when you have the value but need a different unit.
Last updated: May 2026
Enter a 3-digit capacitor code to decode it.
Formula: pF = (d1×10 + d2) × 10d3
How the 3-digit capacitor code works
Ceramic and film capacitors too small to print the full value use a 3-digit code. The first two digits are the significant figures. The third digit is the multiplier exponent, the number of zeros to append. The result is always in picofarads (pF). Decoding the marking is usually the first step before the reactance and filter work you will find across the wider Electronics calculators hub.
Examples: 104 = 10 × 104 pF = 100,000 pF = 100 nF = 0.1 µF. 472 = 47 × 102 pF = 4,700 pF = 4.7 nF. 221 = 22 × 101 pF = 220 pF.
Special third-digit codes: 8 means ×0.01, 9 means ×0.1, used for sub-100 pF values in some manufacturers' coding. Codes under 100 (e.g. "47" with no third digit) are read as direct pF values.
Common capacitor value reference
| Code | pF | nF | µF | Typical use |
|---|---|---|---|---|
| 100 | 10 pF | 0.01 nF | - | RF tuning, small bypass |
| 101 | 100 pF | 0.1 nF | - | HF bypass, filter |
| 102 | 1,000 pF | 1 nF | 0.001 µF | High-frequency decoupling |
| 103 | 10,000 pF | 10 nF | 0.01 µF | Snubber, coupling |
| 104 | 100,000 pF | 100 nF | 0.1 µF | Bypass / decoupling (most common) |
| 105 | 1,000,000 pF | 1,000 nF | 1 µF | Power supply filter |
| 472 | 4,700 pF | 4.7 nF | 0.0047 µF | Audio coupling, timing |
| 226 | 22,000,000 pF | 22,000 nF | 22 µF | Bulk filter (electrolytic equiv.) |
Reading a printed cap code back into farads
This page sits in the part-identification stretch of the DC build chain. Before you arrive here, the Ohm's Law calculator pins down your four base numbers, the LED resistor calculator sizes the current-limiting series resistor, and the voltage divider calculator sets any reference or signal-scaling rail. The companion part-ID step is the resistor color code decoder. You are here: decode a capacitor code, the step where you confirm that the tiny part in your hand actually matches the value your schematic calls for. The one gotcha that trips everyone at least once: the 3-digit code is always in picofarads, so 104 means 10 followed by four zeros, which is 100,000 pF, not 104 of anything. Once the value is confirmed, the next DC step is the watts, volts and amps calculator to size the supply, then the voltage drop calculator for long wiring runs, and finally the battery life calculator for runtime estimates. For AC circuits where capacitor reactance matters rather than stored charge, the capacitor reactance calculator picks up directly from the value you just decoded here.
Frequently Asked Questions
What does the letter after the code mean (e.g. 104K, 104M)?
The letter is the tolerance code. K = ±10%, M = ±20%, J = ±5%, F = ±1%, G = ±2%. So "104K" is 100 nF ±10%. You may also see a voltage rating suffix (e.g. 104K50 = 100 nF, ±10%, 50 V). Ignore the letters when decoding the capacitance value, only the three digits matter.
Why is the 0.1 µF capacitor so common on PCBs?
A 100 nF (0.1 µF) ceramic capacitor placed close to each IC power pin suppresses high-frequency noise that travels along the supply rail. Digital chips switch millions of times per second; each switch draws a brief current spike. A local ceramic cap delivers that charge instantly, before the noise can reach other parts of the board. It is the single most commonly used passive component in digital design.
My schematic says 100 nF but the bin is marked 104. Are they the same part?
Yes. Code 104 decodes to 10 followed by four zeros in picofarads, which is 100,000 pF, or 100 nF, or 0.1 µF. They are all the same capacitance, just expressed in different units. The confusion is common because datasheets list the value in µF, BOMs often use nF, and the physical part uses pF in its code. Moving between them is a factor of 1,000 each step: divide pF by 1,000 to get nF, divide again by 1,000 to get µF.
Can I use a ceramic 104 capacitor instead of an electrolytic?
For bypass and decoupling, yes, ceramic capacitors are preferred because they have lower ESR (equivalent series resistance) and no polarity. For bulk energy storage in power supplies (100 µF+), you still need electrolytic or tantalum capacitors because ceramics in those values are large and expensive. Many modern designs use a combination: one large electrolytic for bulk filtering and one 100 nF ceramic per IC for high-frequency bypass.
Methodology and sources
This tool decodes the 3-digit code printed on ceramic and film capacitors into picofarads, then expresses the same value in nanofarads and microfarads. It follows the standard EIA / IEC capacitor marking convention, where the first two digits are significant figures and the third is a power-of-ten multiplier.
- Method: pF = (d1 × 10 + d2) × 10^d3, where d1 and d2 are the first two digits and d3 is the multiplier digit. Special multipliers: digit 8 means × 0.01 and digit 9 means × 0.1. Unit steps are each a factor of 1,000: nF = pF / 1000 and µF = pF / 1000000.
- Standards and sources: EIA / IEC 60062 capacitor marking convention (three-digit significant-figure-plus-multiplier code and tolerance lettering, for example K = ±10%, M = ±20%, J = ±5%). The unit conversions are standard SI prefix arithmetic; no measurement standard is involved.
- Assumptions and limits: assumes the marking uses the common 3-digit pF convention. Two-digit and "R" (decimal point) markings are read as direct pF values. The result is nominal capacitance only; it does not account for the tolerance letter, voltage rating, dielectric class (such as C0G/NP0 or X7R) or temperature drift, which you must read from the part's full marking or datasheet.
Reviewed and maintained by Rick Oosterling, who builds and wires 12 V, solar and EV systems hands-on. Last reviewed: June 2026. This is a planning and reference aid, not a substitute for the component's datasheet; always confirm capacitance, tolerance and voltage rating against the manufacturer's specification before use.
Next step in this workflow
Code decoded: now check the capacitor's reactance at your operating frequency.