How do I read a 3-digit capacitor code?

The first two digits are the significant figures and the third is the power-of-ten exponent. The result is in picofarads. So 104 means 10 x 10^4 = 100,000 pF = 100 nF = 0.1 µF. The special cases are exponent 8 (x0.01) and exponent 9 (x0.1) for sub-picofarad values.

What is the value of a 104 capacitor?

104 decodes to 10 x 10^4 = 100,000 pF = 100 nF = 0.1 µF. This is one of the most common decoupling values, used across virtually every digital circuit to filter power-supply noise at the IC power pins.

What do the tolerance letters B, C, D, F, G, J, K, M mean?

B = ±0.1 pF, C = ±0.25 pF, D = ±0.5 pF (all absolute, for small values). F = ±1%, G = ±2%, J = ±5%, K = ±10%, M = ±20%, N = ±30% (all percentage). J, K and M are by far the most common on general-purpose ceramics. Precision film capacitors use F or G.

What does the voltage code letter mean?

After the 3-digit body code and tolerance letter, some parts add an EIA-198 voltage rating letter. L means 100 V, H means 50 V, J means 63 V, and so on. Not all manufacturers use this suffix — check the datasheet if absent.

Can I go backwards from capacitance to code?

Yes. Switch to "Capacitance to Code" mode, type the value and choose pF, nF or µF. The tool finds the 3-digit EIA code that exactly represents that value. Only values that land on an EIA significant-figure step (10–99 significant digits) have valid codes; intermediate values will show an error.

Why does my code start with 0, like 010?

Single-significant-digit values below 10 pF are sometimes encoded with a leading zero. 010 means 1 x 10^0 = 1 pF. Codes starting with 00x are rare and usually represent sub-picofarad values that require exponent 8 or 9.

Is this calculator accurate for SMD capacitors?

Yes. Surface-mount ceramics use exactly the same 3-digit EIA coding system as through-hole parts. The only difference is that very small 0201 and 0402 packages sometimes use a 2-character code — that system is not covered here; use the 3-digit decoder for any part where you see three numeric digits.

Capacitor Code Calculator

Surface-mount and through-hole ceramic capacitors are far too small to print a human-readable value in full. Instead, manufacturers stamp a 3-digit EIA code on the body — and often follow it with a tolerance letter and a voltage rating letter. This calculator decodes any such marking into capacitance in picofarads (pF), nanofarads (nF) and microfarads (µF), or works in reverse: type in a capacitance and it returns the correct EIA body code to order or mark on a schematic. Everything runs in your browser; no data is uploaded.

How the 3-digit code works

The system is standardised in IEC 60062 (internationally) and EIA-198 (USA). The rule is simple:

C (pF) = significant × 10^exponent

where the first two printed digits form the significant figure (10–99) and the third digit is the exponent (0–7 gives ×1 through ×10,000,000). Two special exponents handle sub-picofarad values: 8 means ×0.01 and 9 means ×0.1.

For example:

104 → significant = 10, exponent = 4 → 10 × 10,000 = 100,000 pF = 100 nF = 0.1 µF
472 → significant = 47, exponent = 2 → 47 × 100 = 4,700 pF = 4.7 nF
220 → significant = 22, exponent = 0 → 22 × 1 = 22 pF
339 → significant = 33, exponent = 9 → 33 × 0.1 = 3.3 pF

Tolerance letters (IEC 60062)

The letter printed directly after the body code defines the manufacturing tolerance:

Letter	Tolerance	Typical use
B	±0.1 pF	Precision, small values
C	±0.25 pF	Precision, small values
D	±0.5 pF	Precision, small values
F	±1%	Precision film
G	±2%	Precision film
J	±5%	General purpose
K	±10%	General purpose
M	±20%	Bypass / decoupling
Z	+80%/−20%	Electrolytic-style

The calculator shows the absolute min/max capacitance for your code and tolerance combination, so you can immediately see the real spread you are working with.

Voltage rating letters (EIA-198)

Some parts add a third suffix letter for the rated working voltage — L = 100 V, H = 50 V, J = 63 V, A = 1000 V, and so on. The full table is in the voltage selector dropdown. Not all manufacturers use this suffix, so always cross-check the datasheet.

Worked example — decode 104KL

Field	Value
Body code	104
Significant figures	10
Exponent	10^4 = 10,000
Capacitance	100,000 pF = 100 nF = 0.1 µF
Tolerance (K)	±10% → 90 nF to 110 nF
Voltage (L)	100 V rated

This is an extremely common decoupling capacitor. You will find 104K or 104KL printed on the 100 nF 100 V ceramics used on virtually every through-hole development board.

Worked example — encode 4.7 nF

Enter 4.7 in the value field and select nF. The tool converts this to 4,700 pF and finds the code 472 (significant = 47, exponent = 2). Add K for ±10% and L for 100 V and the full marking is 472KL.

Every calculation is performed locally in your browser using the IEC 60062 formula — no server call, no tracking, no data stored.