Reference Guide

Capacitor Codes: 104/103 Values and Tolerance Code J

Confused by "104J", "2A474K", or wrong value can damage your circuit. Use our simple charts to decode any capacitor instantly. Once identified, verify it works with our Capacitor Testing Guide.

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The 3-Digit Code Rule

104

Example Code: 104

1st Digit

First significant figure

2nd Digit

Second significant figure

Multiplier

Add 4 zeros (0000) to the end

Result: 100,000 pF

= 100 nF = 0.1 µF

Common Codes Reference Table

Code	pF (Pico)	nF (Nano)	µF (Micro)
101	100 pF	0.1 nF	0.0001 µF
102	1,000 pF	1 nF	0.001 µF
103	10,000 pF	10 nF	0.01 µF
104	100,000 pF	100 nF	0.1 µF
223	22,000 pF	22 nF	0.022 µF
224	220,000 pF	220 nF	0.22 µF
334	330,000 pF	330 nF	0.33 µF
473	47,000 pF	47 nF	0.047 µF
474	470,000 pF	470 nF	0.47 µF
105	1,000,000 pF	1,000 nF	1.0 µF

Tolerance Letter Codes

The letter after the numbers indicates how precise the capacitor is. "J" is very common (±5%).

± 1%

Precision / Film

± 2%

Precision / Film

± 5%

Standard Film

± 10%

Ceramic X7R

± 20%

Electrolytic / Z5U

+80% / -20%

Disc Ceramic (Old)

Reverse Engineering Tip: The tolerance letter often hints at the capacitor type. If you see a 104J, it's likely a high-quality Film capacitor. If it's 104Z, it's likely a cheap Disc Ceramic.

Wait! Do you see "X2" or "Y2"?

If your capacitor has markings like X1, X2, Y1, or Y2 (often with many safety logos like UL, VDE), it is a Safety Capacitor designed for AC mains filtering.

DO NOT replace these with standard generic capacitors. You must replace them with the exact same Safety Class (e.g., replace an X2 with an X2) to maintain fire safety and shock protection compliance.

Voltage Rating Codes

Sometimes voltage is written directly (e.g., "50V"). Other times, a code is used. Always ensure your replacement capacitor has a voltage rating equal to or higher than the original.

Code	Voltage (DC)	Code	Voltage (DC)
0J	6.3V	2A	100V
1A	10V	2Q	110V
1C	16V	2B	125V
1E	25V	2E	250V
1V	35V	2G	400V
1H	50V	2J	630V
1J	63V	3A	1000V (1kV)

Capacitor Codes FAQ

What does 104 mean on a capacitor?

104 is a 3-digit code measuring measurement in picofarads (pF). The first two digits (10) are significant figures. The third digit (4) is the number of zeros to add. So 104 = 10,0000 pF = 100,000 pF. This converts to 100nF or 0.1µF.

What does the letter J mean on a capacitor?

The letter indicates tolerance (precision). J = ±5%. If you buy a 100µF capacitor with a "J" code, the actual value will be between 95µF and 105µF. Common codes: J=±5%, K=±10%, M=±20%.

How do I read voltage codes like 2A?

Voltage codes use a number-letter system. 2A = 100V DC. 1H = 50V DC. 2E = 250V DC. If you see just a number like "50V", that is the direct voltage rating. Always replace a capacitor with one of equal or higher voltage rating.

What is 100nK?

100n means 100 nanoFarads (which is 0.1µF). The "K" is the tolerance of ±10%. So "100nK" = 0.1µF ±10%.

What is the difference between µF, nF, and pF?

They are units of capacitance. 1 µF (micro) = 1,000 nF (nano) = 1,000,000 pF (pico). To convert pF to µF, move the decimal point 6 places to the left. 100,000pF = 0.1µF.

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