The 3-digit capacitor code translates directly to picofarads (pF). The first two digits are the significant figures, and the third digit is the multiplier (the number of zeros to add). For the most common code you will encounter on the bench: 104 means 10 followed by 4 zeros = 100,000 pF, which converts to 100 nF or 0.1 µF.
While memorizing a few codes is easy, designing a reliable power delivery network or RF filter requires understanding how these base values shift under real-world voltage and temperature stress. Below is the complete reference chart, the derating multipliers you must apply, and a concrete decision path to select your exact part number.
How to Read the Capacitor Value Chart
The master table below is governed by the EIA-198 / IEC 60062 standard for marking codes on small ceramic and film capacitors. Before looking up your value, determine which column applies to your specific installation:
- Picofarads (pF) column: Use this when working with RF circuits, oscillator tank circuits, or high-frequency filtering (typically values under 1 nF).
- Nanofarads (nF) column: Use this for audio coupling, intermediate frequency (IF) filters, and general signal conditioning (1 nF to 999 nF).
- Microfarads (µF) column: Use this for power rail decoupling, bulk energy storage, and low-frequency bypassing (1 µF and above).
The Master Capacitor Value Chart (EIA / IEC 60062)
This table includes the standard E-series preferred values most commonly stocked by distributors like Digi-Key and Mouser. Bookmark this section for quick lookups during PCB layout or breadboard prototyping.
| 3-Digit Code | Picofarads (pF) | Nanofarads (nF) | Microfarads (µF) | Common Application |
|---|---|---|---|---|
| 100 | 10 pF | 0.01 nF | 0.00001 µF | RF matching, VCO tanks |
| 101 | 100 pF | 0.1 nF | 0.0001 µF | High-frequency bypass |
| 102 | 1,000 pF | 1 nF | 0.001 µF | Snubber circuits, EMI filtering |
| 103 | 10,000 pF | 10 nF | 0.01 µF | Audio coupling, IF filters |
| 104 | 100,000 pF | 100 nF | 0.1 µF | Standard IC decoupling (VCC to GND) |
| 105 | 1,000,000 pF | 1,000 nF | 1.0 µF | Local bulk decoupling |
| 222 | 2,200 pF | 2.2 nF | 0.0022 µF | Resonant circuits, timing |
| 223 | 22,000 pF | 22 nF | 0.022 µF | Active filter networks |
| 224 | 220,000 pF | 220 nF | 0.22 µF | Signal coupling, motor suppression |
| 472 | 4,700 pF | 4.7 nF | 0.0047 µF | Crystal oscillator load caps |
| 473 | 47,000 pF | 47 nF | 0.047 µF | Timing circuits (555 timers) |
| 474 | 470,000 pF | 470 nF | 0.47 µF | Power supply smoothing |
Voltage and Temperature Derating: Modifying the Base Value
The chart above tells you the nominal value at 1 kHz and 0V DC bias. In practice, ceramic capacitors—specifically Class II dielectrics like X5R, X7R, and Y5V—suffer severe capacitance loss when DC voltage is applied. This is known as DC bias derating.
To find your effective capacitance, multiply the base value from the chart by the retention multiplier below. For a deep dive into specific part behaviors, engineers rely on tools like the Kemet KSIM simulator to graph exact DC bias curves.
| Dielectric Class | Applied Voltage (vs Rated) | Capacitance Retention | Design Multiplier |
|---|---|---|---|
| C0G / NP0 (Class I) | Any up to 100% | 100% | 1.0 (No derating) |
| X7R (Class II) | 50% of Rated V | ~85% | 0.85 |
| X7R (Class II) | 80% of Rated V | ~60% | 0.60 |
| X5R (Class II) | 50% of Rated V | ~70% | 0.70 |
| X5R (Class II) | 80% of Rated V | ~30% | 0.30 |
| Y5V (Class III) | 50% of Rated V | ~20% | 0.20 |
Decision Tree: Picking the Exact Part Number
Use this decision path to move from a schematic value to a concrete, orderable part number. Do not leave your BOM with generic '100nF 50V' descriptions.
| If Your Circuit Requires... | Then Choose Dielectric... | And Package/Voltage... | Concrete Part Pick (Order This) |
|---|---|---|---|
| Standard 0.1µF (104) decoupling for 5V/3.3V logic ICs | X7R (Stable, cheap, low ESL) | 0603 or 0805, 16V or 25V rated | Kemet C0805C104K5RACTU (0805, 0.1µF, 50V, X7R) |
| Precision timing or RF filtering where capacitance cannot drift | C0G / NP0 (Zero DC bias/temp drift) | 0402 or 0603, 50V rated | Murata GRM1885C1H101JA01 (0603, 100pF, 50V, C0G) |
| Bulk 10µF decoupling on a 12V or 24V power rail | X7R or Polymer (Avoid X5R at high V) | 1206 or 1210, minimum 50V rated | Murata GRM32ER71H106KA12 (1210, 10µF, 50V, X7R) |
| Audio signal coupling (blocking DC, passing 20Hz-20kHz) | X7R or Film (Avoid Y5V microphonics) | 0805, 16V or 25V rated | Samsung CL21B104KBFNNNE (0805, 0.1µF, 50V, X7R) |
What the Chart Cannot Tell You (And How to Compensate)
A 3-digit code only defines nominal capacitance. To ensure your design survives the jobsite or the bench, you must check three parameters that the value chart completely ignores:
- Equivalent Series Resistance (ESR): Critical for switching power supplies. A standard 104 X7R ceramic might have an ESR of 5 milliohms, which is great for high-frequency decoupling but terrible for damping. If you need high ESR for loop stability in an LDO regulator, you must intentionally select a tantalum or electrolytic capacitor, or add a discrete series resistor.
- Ripple Current Rating: Ceramic capacitors handle high ripple well, but aluminum electrolytics will literally vent and dry out if their RMS ripple current limit is exceeded. Always check the manufacturer's datasheet for the ripple current specification at your specific switching frequency (e.g., 100kHz vs 120Hz).
- Piezoelectric Microphonics: Class II ceramics (X7R, X5R) are piezoelectric. They act as microphones, converting mechanical vibration into electrical noise, and as speakers, emitting audible whine under AC ripple. If you are designing a low-noise analog front-end or an audio DAC, never use X7R for the bulk filtering. Use C0G ceramics, film capacitors, or place the X7R caps on the opposite side of the PCB from sensitive traces. For comprehensive layout strategies, refer to Texas Instruments' decoupling guidelines.
By combining the base 3-digit lookup with proper DC bias derating and an awareness of parasitic ESR, you will eliminate the most common passive component failures before your board ever goes to fab.
