Resistor Color Code Calculator
Read a resistor from its 3, 4, 5 or 6 colour bands, or turn a value into bands. Shows tolerance, temperature coefficient and the nearest E12, E24 or E96 value.
The interactive tool loads here when JavaScript runs.
About this toolWhat is the Resistor Color Code Calculator?
Click the colour of each band and the calculator reads the resistor for you: resistance, tolerance, the minimum and maximum it may measure, and on six-band parts the temperature coefficient. A drawing of the resistor updates with every click, so you can hold the real part next to the screen and compare.
Switch to "Value to colours" to go the other way. Type a value such as 4.7 kΩ, choose four, five or six bands and a tolerance, and the tool shows the bands to look for. It also lists the nearest standard values in the E12, E24 and E96 series, with how far each is from the value you typed, which helps when a calculation gives you a resistance nobody stocks.
Colours, tolerances and temperature coefficients follow IEC 60062:2016, the international standard for component marking codes.
- 3, 4, 5 and 6-band decoding to IEC 60062:2016
- Value to colour bands, with rounding noted
- Nearest E12, E24 and E96 values with percentage error
- Live resistor drawing and tolerance range
- Copy and share the result; nothing leaves your browser
How to use the Resistor Color Code Calculator
- Choose how many bands the resistor has: 3, 4, 5 or 6.
- Hold the resistor so the bunched bands are on the left. The tolerance band is usually set a little apart on the right, and gold or silver never appears first.
- Click the colour of each band in order. Only colours that are valid for that position are offered.
- Read the resistance, tolerance range and temperature coefficient, and check the E-series lines to see whether it is a standard value.
- To find bands for a value, switch to "Value to colours", type the resistance, pick the unit, band count and tolerance, and read the colours and nearest standard values.
Worked examples
Yellow, violet, red, gold
Input
4 bands
Output
4.7 kΩ ±5%, so anything from 4.465 kΩ to 4.935 kΩ is in spec
Digits 4 and 7 make 47, red multiplies by 100, and gold is ±5%. It is a standard E12 value.
A precision 6-band part
Input
Red, red, black, brown, brown, brown
Output
2.2 kΩ ±1%, 100 ppm/K (about 0.22 Ω per °C)
Three digits 220, brown multiplier ×10, brown tolerance ±1% and a brown temperature coefficient band of 100 ppm/K.
Bands for a calculated 5 kΩ
Input
Value to colours, 5 kΩ, 4 bands, ±5%
Output
Green, black, red, gold. Nearest E12 4.7 kΩ (−6%), E24 5.1 kΩ (+2%), E96 4.99 kΩ (−0.2%)
5 kΩ can be printed on a band code but is not a stock value. A 5.1 kΩ 5% part or a 4.99 kΩ 1% part is what you would actually buy.
A 12.4 kΩ 1% resistor
Input
Value to colours, 12.4 kΩ, 5 bands, ±1%
Output
Brown, red, yellow, red, brown
Three digits 124 times red (×100). Values with three significant digits need a 5- or 6-band code.
Background and insight
Colour bands date from the 1920s, when the Radio Manufacturers Association needed a marking that survived soldering heat and could be read on tiny parts. The digits follow the spectrum from black (0) through brown, red, orange, yellow, green, blue, violet and grey to white (9), and the multiplier band uses the same colours as powers of ten, with gold for ×0.1, silver for ×0.01 and, since the 2016 edition of IEC 60062, pink for ×0.001.
A 4-band resistor has two significant digits, a multiplier and a tolerance. Five- and six-band resistors have three digits, which precision values in the E48, E96 and E192 series need, and the sixth band gives the temperature coefficient in ppm per kelvin (brown 100, red 50, orange 15, yellow 25, blue 10, violet 5). Tolerance colours are brown ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, gold ±5% and silver ±10%; a missing band means ±20%. IEC 60062:2016 also assigns orange ±0.05%, yellow ±0.02% and grey ±0.01%, although some older parts use grey for ±0.05%.
Standard values come from the IEC 60063 preferred number series. Each E-series splits a decade into steps of equal ratio: E12 has 12 values (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) suited to ±10% parts, E24 has 24 for ±5% parts, and E96 has 96 for ±1% parts. Because the steps are geometric, the calculator finds the nearest standard value by ratio rather than by plain difference.
Common use cases
Sorting a parts drawer
Identify loose resistors quickly, including faded or unusual colours, without measuring each one.
Building a kit
Check that each resistor matches the value on the parts list before soldering it in.
Repairing old equipment
Read the code on a burnt or discoloured part, then find the nearest current standard value to replace it.
Specifying a design
Round a calculated resistance to the nearest E24 or E96 value and see how far off it is.
Tips and limitations
- If you are unsure which end to start from, try both orientations. Only one usually gives a sensible value with a tolerance band at the end.
- Brown and red, or orange and red, look alike under warm light. A multimeter settles it in seconds.
- Heat discolours bands. A resistor that has run hot may show brown where it was once orange, so measure suspect parts.
- Surface-mount resistors use printed number codes (such as 472 or 4701) instead of bands.
- Blue-bodied resistors are often metal film with 1% tolerance and five bands; beige-bodied carbon film parts are usually 5% with four bands.
Frequently asked questions
How do you read a 4-band resistor colour code?
The first two bands are digits, the third is the multiplier (number of zeros) and the fourth is tolerance. Yellow, violet, red, gold is 4, 7 and two zeros, so 4,700 Ω (4.7 kΩ) at ±5%.
Which end of the resistor do I start reading from?
Start from the end with the bands grouped closest to it. The tolerance band, often gold or silver, sits a little further away on the other end. Gold and silver are never the first band.
What does the sixth band on a resistor mean?
It is the temperature coefficient: how much the resistance changes per degree, in parts per million per kelvin. Brown is 100 ppm/K, red 50, yellow 25, orange 15, blue 10 and violet 5.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor has three significant digits instead of two, so it can show precision values like 4.99 kΩ or 12.4 kΩ. Five-band parts are usually 1% or better; four-band parts are usually 5%.
What is the colour code for a 10k resistor?
Four bands: brown, black, orange, then the tolerance (gold for 5%). Five bands: brown, black, black, red, then the tolerance (brown for 1%).
What are E12, E24 and E96 values?
They are the IEC 60063 standard value series, with 12, 24 and 96 values per decade spaced by equal ratios. Manufacturers stock resistors in these values, so a calculated resistance is normally rounded to the nearest one.
What does a gold or silver multiplier band mean?
Gold as the multiplier divides by 10 and silver divides by 100. Orange, orange, gold, gold is 33 × 0.1 = 3.3 Ω at ±5%.
Is there an in-depth guide to the Resistor Color Code Calculator?
Yes. “Ohm's Law, Resistor Color Codes and Voltage Drop Explained” covers the background, how it works, common pitfalls and worked examples. Read the full guide.
Related Tools You May Like
Free, in-browser tools that pair well with this one.