Tap each band on the resistor and pick its color: the value, the tolerance and the actual min–max range show up right away. It works the other way too: type a value such as 220, 4k7 or 1M and the bands are drawn for you.
It follows the IEC 60062 color code (the resistor colour code in UK and Indian textbooks) and checks whether the result is a standard E12, E24 or E96 value, which quickly catches a resistor read backwards.
How to use
- Choose how many bands your resistor has. 4 bands is the most common; 5 and 6-band resistors are precision parts.
- Hold the resistor with the gold or silver band on the right. Tap each band in the drawing and pick the color you see.
- Read the value, tolerance and range. If it isn't a standard value, tap Flip: you may be reading it from the wrong end.
- To go the other way, type the value in the box and the colors update. Copy link shares the exact result.
Resistor color code chart
| Color | Digit | Multiplier | Tolerance | Temp. coefficient |
|---|---|---|---|---|
| Black | 0 | ×1 | 250 ppm/K | |
| Brown | 1 | ×10 | ±1% | 100 ppm/K |
| Red | 2 | ×100 | ±2% | 50 ppm/K |
| Orange | 3 | ×1 k | ±0.05% | 15 ppm/K |
| Yellow | 4 | ×10 k | ±0.02% | 25 ppm/K |
| Green | 5 | ×100 k | ±0.5% | 20 ppm/K |
| Blue | 6 | ×1 M | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10 M | ±0.1% | 5 ppm/K |
| Grey | 8 | ×100 M | ±0.01% | 1 ppm/K |
| White | 9 | ×1 G | ||
| Gold | ×0.1 | ±5% | ||
| Silver | ×0.01 | ±10% | ||
| Pink | ×0.001 | |||
| No band | ±20% |
How to read a resistor color code
The first bands are digits, the next is the multiplier (how many zeros to add) and the last is the tolerance. On a 4-band resistor, red, red, brown, gold means 2, 2, ×10, ±5%: 220 Ω.
5 and 6-band resistors have a third digit, so they can show values like 4.99 kΩ (yellow, white, white, brown). The sixth band is the temperature coefficient: how many parts per million the value drifts per degree.
Which way to read the bands
The tolerance band usually sits a little apart from the others, and gold or silver never comes first. If the gaps look the same, read it both ways: usually only one direction gives a standard value. On 5-band resistors brown often shows up at both ends, so the standard value check is the quickest way to decide.
When the colors are hard to tell apart
Old or overheated resistors change color: red can look orange or brown, and blue bodies make the bands harder to read. When in doubt, take the resistor out of the circuit and measure it with a multimeter on the ohms range.