Ceramic capacitors: how to read 3-digit plus 1-letter markings?

The numbers work like a resistor.

The first two numbers are just numbers.

The third number is the number of 0's after. It's in picofarads.

So:

• 103 is 1 0 000 or 10,000pf or 10nF
• 104 is 1 0 0000 or 100,000pf or 100nF

The letter next is the tolerance:

B   +/- 0.10pF
C   +/- 0.25pF
D   +/- 0.5pF
E   +/- 0.5%
F   +/- 1%
G   +/- 2%
H   +/- 3%
J   +/- 5%
K   +/- 10%
M   +/- 20%
N   +/- 30%
P   +100% ,-0%
Z   +80%, -20% 

Anything after that is usually manufacturer specific.

The "Z" tolerance is most often omitted. If there is no letter after the value then assume it to be "Z". IE: The actual value could be double the shown value or 80% of the shown value - or anything in between. These are suitable as noise decoupling and/or differential coupling applications. Note that they should NOT be used in any kind of timing or oscillator circuits unless the timing or frequency can be suitably adjusted after construction. Also be aware of temperature stability - they usually vary their values considerably with temperature variations.