A 3-digit capacitor code like 104 translates directly to 100,000 pF (which equals 100 nF or 0.1 µF). The first two digits represent the significant figures, and the third digit is the multiplier (the number of zeros to add), with the base unit always in picofarads (pF). This marking system is governed by the EIA RS-198 and IEC 60062 standards for ceramic and film capacitors.
While reading the base value is straightforward, assuming a "104" capacitor will actually provide 100 nF in your circuit is a common bench mistake. The actual capacitance shifts dramatically based on the dielectric material, applied DC voltage, and operating temperature. Below is the master reference chart, followed by the critical derating modifiers you need to calculate real-world performance.
The Master Capacitor Code Chart (EIA 3-Digit Standard)
How to read this table: The Code column is what is printed on the component body. The 1st & 2nd Digit and Multiplier columns show the mathematical breakdown. The final three columns provide the converted values in picofarads (pF), nanofarads (nF), and microfarads (µF). Which column applies to your circuit? If you are breadboarding audio circuits or designing low-frequency power filters, read the nF or µF column. If you are designing RF oscillators, antenna matching networks, or high-speed digital decoupling, you must think in pF to account for parasitic resonance and trace inductance.
| Code | 1st & 2nd Digit | Multiplier (Zeros) | Value (pF) | Value (nF) | Value (µF) |
|---|---|---|---|---|---|
| 100 | 10 | 0 | 10 pF | 0.01 nF | 0.00001 µF |
| 101 | 10 | 1 | 100 pF | 0.1 nF | 0.0001 µF |
| 102 | 10 | 2 | 1,000 pF | 1 nF | 0.001 µF |
| 103 | 10 | 3 | 10,000 pF | 10 nF | 0.01 µF |
| 104 | 10 | 4 | 100,000 pF | 100 nF | 0.1 µF |
| 105 | 10 | 5 | 1,000,000 pF | 1,000 nF | 1.0 µF |
| 222 | 22 | 2 | 2,200 pF | 2.2 nF | 0.0022 µF |
| 223 | 22 | 3 | 22,000 pF | 22 nF | 0.022 µF |
| 224 | 22 | 4 | 220,000 pF | 220 nF | 0.22 µF |
| 472 | 47 | 2 | 4,700 pF | 4.7 nF | 0.0047 µF |
| 473 | 47 | 3 | 47,000 pF | 47 nF | 0.047 µF |
| 474 | 47 | 4 | 470,000 pF | 470 nF | 0.47 µF |
Source: Electronic Industries Alliance (EIA) RS-198 / IEC 60062 marking standards for fixed capacitors.
- 104: 100 nF (0.1 µF) — The universal decoupling cap for 5V/3.3V logic ICs.
- 103: 10 nF (0.01 µF) — Standard high-frequency bypass and snubber value.
- 222: 2.2 nF — Common in RF filtering and 555 timer astable circuits.
- 473: 47 nF (0.047 µF) — Frequently used in audio crossover and tone-control networks.
Tolerance, Voltage, and Temperature Coefficient Modifiers
The 3-digit code only tells you the nominal base value at room temperature (25°C) with zero DC bias applied. To know how the component will actually behave on your PCB, you must read the alphanumeric suffixes that follow the main code.
How Derating Modifies the Base Value
Unlike C0G/NP0 (Class I) capacitors, which are virtually immune to environmental shifts, Class II dielectrics (like X7R, X5R, and Y5V) suffer from severe capacitance loss under heat and voltage. How do these derating rows modify your base value? If you place a 10 µF (code 106) X5R capacitor in a 12V circuit, the applied DC bias compresses the dielectric's internal dipoles. According to Murata's technical documentation on DC bias characteristics, that "10 µF" part might actually deliver only 2.5 µF of effective capacitance at 12V. Similarly, a Y5V capacitor rated for 85°C can lose up to 80% of its base value when operating at its maximum temperature limit.
| EIA Code | Class | Temp Range | Max Capacitance Change | Best Application |
|---|---|---|---|---|
| C0G / NP0 | I | -55°C to +125°C | ±30 ppm/°C (Virtually 0%) | RF tuning, precision oscillators, filters |
| X7R | II | -55°C to +125°C | ±15% | General decoupling, power supply bypass |
| X5R | II | -55°C to +85°C | ±15% | High-density MLCCs, consumer electronics |
| Y5V | II | -30°C to +85°C | +22% / -82% | Non-critical bulk decoupling (Avoid for timing) |
Tolerance Letters
Following the numeric code and dielectric letter, you will often find a single tolerance letter. For precision analog circuits, you must select tight tolerances; for power rail decoupling, loose tolerances are acceptable and cheaper.
- C: ±0.25 pF (Used for values under 10 pF)
- J: ±5% (Standard for precision audio and RF)
- K: ±10% (The most common commercial-grade tolerance)
- M: ±20% (Standard for bulk electrolytic and high-value ceramics)
- Z: +80% / -20% (Legacy code, mostly found on older Y5V ceramics)
What This Chart Cannot Tell You (And How to Verify)
A capacitor code chart is a static translation tool. It cannot predict dynamic circuit behavior. When designing high-reliability or high-frequency boards, you must look beyond the 3-digit stamp.
The Hidden Multipliers: ESR, ESL, and Microphonics
The chart gives you capacitance, but it completely omits Equivalent Series Resistance (ESR) and Equivalent Series Inductance (ESL). A 104 (100 nF) capacitor in a large 1206 surface-mount package will have a much higher ESL than the same 104 value in a tiny 0402 package. In a high-speed digital circuit, the ESL of the larger package will cause the capacitor to self-resonate and become an inductor at a much lower frequency, rendering it useless for high-frequency noise suppression. Furthermore, Class II ceramics exhibit piezoelectric microphonics—they can act as microphones, picking up mechanical vibration and injecting it into your analog signal path as electrical noise.
How to Properly Measure and Verify
Do not rely on a standard digital multimeter's capacitance setting to verify high-value MLCCs. Standard DMMs often apply a DC bias during measurement, which artificially suppresses the reading on X5R/X7R parts, leading you to think the component is defective.
To accurately verify a capacitor against its code chart value, use a dedicated LCR meter and apply the correct test frequency based on the IEC 60384 testing standard:
- For codes 104 (100 nF) and below: Measure at 1 MHz with a 1V RMS test signal.
- For codes 105 (1 µF) and above: Measure at 120 Hz or 1 kHz with a 0.5V RMS test signal.
By combining the quick-reference translation of the EIA 3-digit chart with an understanding of dielectric derating and proper LCR measurement techniques, you can confidently select, verify, and debug capacitors in any AC/DC or embedded design.
