Free printable

Printable capacitor code chart

The capacitor codes cheat sheet: how to read the code 104, a pF to nF to µF conversion, a table of 18 common codes, tolerance letters, voltage codes, an electrolytic capacitor symbol, and the E6 values.

A one-page capacitor code chart for the workbench. It shows how to turn a code like 104 or 473J into a value, converts between pF, nF and µF, and decodes the tolerance letters and voltage codes printed on film and ceramic capacitors.

Download PDF (A4)Download PDF (US Letter)

One page. Free to print and share for teaching. Print at actual size (100%), not fit to page. A4 suits most of the world; US Letter suits the USA and Canada.

What's on the sheet

Reading a 3-digit code, with 104 worked through and three more examples
Reading a capacitor, step by step, ending with 2A104J decoded in full
pF, nF and µF: the ÷ 1000 ladder and the other ways values are written, like 4n7
18 common codes from 100 (10 pF) to 106 (10 µF) in all three units
Tolerance letters B to Z and voltage codes 0J to 2J
Electrolytic capacitors: which leg is negative and how to pick a voltage rating
The E6 values capacitors come in, and the ones you'll reach for most

How to use it in class

Give each pair of students a handful of small ceramic capacitors and the chart, and ask them to sort the capacitors from smallest to largest by their codes. Then build an RC timer with two of them and compare the times. The conversion ladder is worth pinning up anywhere students do capacitor sums, since a slip between nF and µF is the most common mistake.

Free lesson

Now build it yourself

Each lesson comes in three short parts: see the idea, try it on a live board, then build it yourself, with quick checks as you go.

Try it yourself: free lesson

“Capacitors” is lesson 1 of 5 in Capacitor Caves, Electronics World 3. Free with an account. Lessons unlock in order, so you’ll do the 15 before it first.

Or start from the very first lesson, no account needed

The charts online

Work it out

The ideas behind it

Questions teachers ask

What does 104 mean on a capacitor?

10 followed by four zeros, in picofarads: 100,000 pF. That's 100 nF, or 0.1 µF, the capacitor that sits by every chip's power pin. The chart lists 18 common codes in pF, nF and µF.

Why are capacitor codes in picofarads?

The code was made for small ceramic and film capacitors, which run from a few pF to a few µF. Counting in pF keeps every value a whole number, so the code needs only three digits.

Which paper size should I print?

A4 for most of the world and US Letter for the USA and Canada. Both fit on one page; print at actual size rather than fit to page so the tables stay crisp.