Capacitor code

Work out the capacitance from the 3-digit code printed on a chip capacitor. Example: 104 = 0.1 µF

Code (3 digits)

Capacitance

0.1µF

History

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Formula

Formula: first two digits × 10^(third digit) [pF]
Example: 104 → 10 × 10⁴ pF = 100,000 pF = 0.1 µF

Design notes

Chip capacitors carry their value as three digits. The first two are the significant figures and the last one is the multiplier — the power of ten.

Codes you will see often:
• 104 → 0.1 µF (the usual decoupling value)
• 103 → 10 nF
• 472 → 4.7 nF
• 220 → 22 pF (RF work)

Handy for identifying an unmarked part in stock, or checking a reel against the BOM before a build.

When you need this

For reading parts off an assembled board, or for turning a three-digit code from a schematic or BOM into a real capacitance. Repair, failure analysis and incoming inspection all involve reconciling parts against paperwork.

Reading the three-digit code

The first two digits are the significant figures and the third is the number of zeros. The unit is pF.

"104" is 10 followed by four zeros: 100000pF = 100nF = 0.1µF. "223" is 22 followed by three zeros: 22000pF = 22nF. It becomes automatic with practice, but the step to µF is where mistakes happen.

Common values

Code	pF	nF	µF	Typical use
101	100 pF	0.1 nF	0.0001 µF	RF bypass
102	1,000 pF	1 nF	0.001 µF	Filtering
103	10,000 pF	10 nF	0.01 µF	Decoupling
104	100,000 pF	100 nF	0.1 µF	The standard decoupling value
105	1,000,000 pF	1,000 nF	1 µF	Bulk supply
106	10,000,000 pF	10,000 nF	10 µF	Bulk supply
224	220,000 pF	220 nF	0.22 µF	Intermediate value
475	4,700,000 pF	4,700 nF	4.7 µF	Bulk supply

Other markings

Codes containing "R". "4R7" is 4.7pF, with R marking the decimal point. Used below 10pF.
One or two bare digits. "47" means 47pF. Distinguish from three-digit codes by context.
Tolerance letters. A trailing letter gives tolerance: J = ±5%, K = ±10%, M = ±20%, F = ±1%.
Temperature characteristic codes. C0G / NP0 (very stable) versus X7R / X5R (high permittivity, larger value but varies with voltage and temperature). This distinction is sometimes more important than the value itself.

Chip capacitors carry no marking. You cannot read the value off the board — you need the schematic or BOM. Measuring in circuit is also unreliable because surrounding components affect the reading.

Frequently asked questions

Why are chip capacitors unmarked?

They are too small to mark, and firing a marking onto the ceramic surface would affect the part. Unlike resistors there is no way to identify the value visually, which makes reel labelling and BOM control important. After assembly you must either measure or consult the schematic.

Are "104" and "0.1µF" the same?

Yes. 104 = 10 × 10⁴ pF = 100,000pF = 100nF = 0.1µF. It is the most common decoupling value, so this conversion is worth having at your fingertips.

When do I use C0G versus X7R?

C0G (NP0) barely varies with temperature or voltage, so use it where precision matters: filter values, oscillators, timing. The trade-off is far less capacitance for a given size. X7R / X5R give large values for decoupling and bulk, but lose substantial capacitance under DC bias.

Are there four-digit codes?

Yes. In the EIA four-digit scheme the first three digits are significant figures and the fourth is the number of zeros. "1002" is 100 followed by two zeros: 10,000pF = 10nF. It is used on precision parts. Tell them apart by digit count.

Standards and references

EIA-198 — Temperature characteristic codes for capacitors (C0G / X7R and others).
IEC 60062 — Marking codes for resistors and capacitors.
IEC 60384-1 — Generic specification for fixed capacitors.

Last updated: 2026-08-29