A standard 3-digit capacitor code like 104 translates directly to 100,000 pF (100 nF or 0.1 µF). The first two digits represent the significant figures (10), and the third digit is the multiplier indicating the number of zeros to append (4 zeros). This EIA/IEC standard coding system allows manufacturers to mark tiny surface-mount and through-hole components without printing cumbersome decimal values. Below is the complete reference chart, followed by the critical derating data you need to calculate real-world effective capacitance.
How to Read the Standard Capacitance Values Chart
The chart below maps the most frequently queried 3-digit EIA codes to their exact Picofarad (pF), Nanofarad (nF), and Microfarad (µF) equivalents. This marking standard is governed by IEC 60062 and the legacy EIA RS-198 standard. When reading the table, the first two columns give you the raw code and the mathematical multiplier. The next three columns provide the converted values. The final column, Common Dielectric Class, is the column that applies directly to your installation environment, dictating how the component will behave under temperature and voltage stress.
| 3-Digit Code | Multiplier | Picofarads (pF) | Nanofarads (nF) | Microfarads (µF) | Common Dielectric Class |
|---|---|---|---|---|---|
| 101 | x 10 | 100 pF | 0.1 nF | 0.0001 µF | C0G (NP0) |
| 102 | x 100 | 1,000 pF | 1 nF | 0.001 µF | C0G / X7R |
| 103 | x 1,000 | 10,000 pF | 10 nF | 0.01 µF | X7R / Y5V |
| 104 | x 10,000 | 100,000 pF | 100 nF | 0.1 µF | X7R / X5R |
| 105 | x 100,000 | 1,000,000 pF | 1,000 nF | 1.0 µF | X5R / X7R |
| 106 | x 1,000,000 | 10,000,000 pF | 10,000 nF | 10.0 µF | X5R / X7S |
| 222 | x 100 | 2,200 pF | 2.2 nF | 0.0022 µF | C0G / X7R |
| 223 | x 1,000 | 22,000 pF | 22 nF | 0.022 µF | X7R |
| 224 | x 10,000 | 220,000 pF | 220 nF | 0.22 µF | X7R / X5R |
| 472 | x 100 | 4,700 pF | 4.7 nF | 0.0047 µF | C0G / X7R |
| 473 | x 1,000 | 47,000 pF | 47 nF | 0.047 µF | X7R |
| 474 | x 10,000 | 470,000 pF | 470 nF | 0.47 µF | X7R / X5R |
For a deeper dive into the underlying marking standards, the International Electrotechnical Commission (IEC) maintains the IEC 60062 specification, which standardizes these alphanumeric codes across global supply chains. Additionally, All About Circuits provides an excellent breakdown of how these codes map to physical component tolerances.
Applying Derating: When Base Values Drop
The chart above provides the nominal capacitance, measured at 0V DC bias and 25°C ambient temperature. In a real circuit, effective capacitance drops. Understanding how derating rows modify the base value is critical for power supply and analog filter design.
How derating modifies the base value: Derating applies a reduction multiplier to the nominal chart value based on two variables: applied DC voltage and ambient temperature. If you place a 10 µF (106) X5R ceramic capacitor (like a Murata GRM21 series) across a 12V rail, the DC bias effect will reduce its effective capacitance. At 12V, the dielectric saturation might apply a 0.4x multiplier, meaning your 10 µF part is only providing 4 µF of actual capacitance to the circuit.
Which column applies to your installation? The Common Dielectric Class column dictates your derating penalty.
- Class I (C0G/NP0): Negligible voltage and temperature derating. The chart value is the real-world value. Use these for RF tanks, precision oscillators, and audio crossovers.
- Class II (X7R, X5R): Moderate to severe DC bias derating (20% to 60% loss at rated voltage). Excellent for general decoupling and bulk power filtering where exact capacitance is less critical than volume efficiency.
- Class III (Y5V): Extreme temperature and voltage derating (up to 80% loss). Avoid these in modern designs unless cost is the absolute primary constraint.
What the Capacitance Values Chart Cannot Tell You
While the EIA code chart is essential for identifying nominal values, it is blind to the parasitic elements that dictate high-frequency performance. When selecting a component for a switching regulator or high-speed digital decoupling, you must consult the manufacturer's datasheet for the following missing parameters:
- Equivalent Series Resistance (ESR): Dictates heat generation under ripple current. A 104 (0.1 µF) X7R capacitor in an 0402 package will have a vastly different ESR than the same value in an 0805 package due to electrode geometry.
- Equivalent Series Inductance (ESL): Determines the self-resonant frequency (SRF). Above the SRF, the capacitor acts as an inductor, rendering it useless for high-frequency decoupling. Smaller physical footprints (like 0201 or 0402) inherently offer lower ESL.
- Ripple Current Rating: The maximum AC current the component can handle without exceeding its thermal limits. This is rarely printed on the part and must be verified via the spec sheet.
- Physical Footprint: The code '105' (1 µF) can be manufactured in a tiny 0402 (1005 metric) package or a massive 1206 (3216 metric) package. The chart tells you nothing about the pad layout required on your PCB.
Frequently Asked Questions
How do I calculate the capacitance value from a 3-digit code?
Take the first two digits as your base number, then multiply by 10 raised to the power of the third digit. For example, code 473: the base is 47, and the multiplier is 3. Calculate 47 x 10^3 (or 47 x 1,000) = 47,000 pF. To convert to microfarads, divide by 1,000,000, yielding 0.047 µF.
What is the difference between X7R and C0G in the capacitance chart?
C0G (also known as NP0) is a Class I dielectric with near-zero temperature and voltage coefficients; its capacitance remains stable regardless of environment. X7R is a Class II dielectric that offers much higher capacitance density in smaller packages but suffers from capacitance loss when subjected to DC voltage bias and temperature extremes. X7R is standard for power decoupling, while C0G is required for precision timing and RF circuits.
Why does my 10uF ceramic capacitor measure lower on my LCR meter?
High-capacitance ceramic capacitors (like 106 / 10 µF) are highly sensitive to the test frequency and test voltage of your LCR meter. If your meter applies a standard 1Vrms test signal at 1 kHz, you will read close to 10 µF. However, if the meter defaults to a lower frequency, or if you are measuring the part while it is biased in-circuit, the reading will drop. Always check your LCR meter's test signal amplitude and frequency against the manufacturer's specified test conditions (usually 0.5Vrms or 1.0Vrms at 120Hz or 1kHz for high-value ceramics).
Are capacitance values standardized across all manufacturers?
Yes, the nominal values and 3-digit EIA codes are strictly standardized under IEC 60062. A 104 code from Murata, KEMET (Yageo), TDK, and Samsung Electro-Mechanics will all nominally equal 100,000 pF. However, the parasitic characteristics (ESR, ESL, DC bias derating curves) and physical dimensions are not standardized and will vary significantly between brands and specific product series.
