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About the resistor color code
A small resistor has no room for printed numbers. Instead it has colored bands. Each color stands for a number, and together the bands give the resistance, the tolerance and, on some resistors, the temperature coefficient.
This calculator reads the bands for you. Tap a band on the drawing, pick its color, and the value appears at once. It also works the other way: type a value like 4.7k or 220 and see the colors to look for. For the tiny SMD parts on circuit boards, a third tab reads printed codes like 103, 4R7 and 01C.
Features
- 4, 5 and 6 bands — carbon resistors with 4 bands, precision resistors with 5, and 6 bands with a temperature coefficient
- Clickable drawing — tap a band on the resistor, then tap its color; the next band is picked for you
- Value → colors — type 4.7k, 4k7 or 4700 and get the bands, rounded to an E12, E24, E48 or E96 standard value if you like
- Tolerance range — the lowest and highest real value, like 4.465 kΩ – 4.935 kΩ
- Standard value check — says if the value is in the E12, E24, E48 or E96 series, or gives the nearest E24 value
- Read from the other end — one tap turns the bands around when you are not sure which side is first
- SMD codes — 3-digit (103), 4-digit (1002), EIA-96 (01C) and R codes (4R7), with the same value in the other codes
The 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 | — | 15 ppm/K |
| Yellow | 4 | × 10 k | — | 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 | ± 0.05 % | 1 ppm/K |
| White | 9 | × 1 G | — | — |
| Gold | — | × 0.1 | ± 5 % | — |
| Silver | — | × 0.01 | ± 10 % | — |
| No band | — | — | ± 20 % | — |
The digits go from black (0) to white (9), with the rainbow in the middle: red, orange, yellow, green, blue, violet. Learn that order and you can read most resistors without a chart.
How to read a 4-band resistor
- Turn the resistor so the gold or silver band is on the right. That is the tolerance band.
- Read the first two bands as digits.
- The third band is the multiplier: the number of zeros to add.
- The fourth band is the tolerance.
Example: Yellow, Violet, Red, Gold
- Yellow = 4, Violet = 7 → 47
- Red = × 100 → 47 × 100 = 4,700 Ω = 4.7 kΩ
- Gold = ± 5 % → the real value is between 4.465 kΩ and 4.935 kΩ
5-band and 6-band resistors
Precision resistors, often with a blue body, have three digit bands, then the multiplier and the tolerance.
Example: Brown, Black, Black, Red, Brown
- Brown, Black, Black = 100
- Red = × 100 → 100 × 100 = 10,000 Ω = 10 kΩ
- Brown = ± 1 % → between 9.9 kΩ and 10.1 kΩ
A 6-band resistor adds one more band at the end: the temperature coefficient. Brown means 100 ppm/K: the value changes by 0.01 % for each degree Celsius of change.
Common values and their colors
| Value | 4 bands (± 5 %) | 5 bands (± 1 %) |
|---|---|---|
| 10 Ω | Brown, Black, Black, Gold | Brown, Black, Black, Gold, Brown |
| 100 Ω | Brown, Black, Brown, Gold | Brown, Black, Black, Black, Brown |
| 220 Ω | Red, Red, Brown, Gold | Red, Red, Black, Black, Brown |
| 330 Ω | Orange, Orange, Brown, Gold | Orange, Orange, Black, Black, Brown |
| 470 Ω | Yellow, Violet, Brown, Gold | Yellow, Violet, Black, Black, Brown |
| 1 kΩ | Brown, Black, Red, Gold | Brown, Black, Black, Brown, Brown |
| 2.2 kΩ | Red, Red, Red, Gold | Red, Red, Black, Brown, Brown |
| 4.7 kΩ | Yellow, Violet, Red, Gold | Yellow, Violet, Black, Brown, Brown |
| 10 kΩ | Brown, Black, Orange, Gold | Brown, Black, Black, Red, Brown |
| 22 kΩ | Red, Red, Orange, Gold | Red, Red, Black, Red, Brown |
| 47 kΩ | Yellow, Violet, Orange, Gold | Yellow, Violet, Black, Red, Brown |
| 100 kΩ | Brown, Black, Yellow, Gold | Brown, Black, Black, Orange, Brown |
| 1 MΩ | Brown, Black, Green, Gold | Brown, Black, Black, Yellow, Brown |
These are the values that most starter kits and Arduino projects use: 220 Ω or 330 Ω for LEDs, 10 kΩ for buttons and pull-up resistors, 4.7 kΩ for I2C pull-ups.
Standard values: E12, E24 and E96
Resistors are not made in every value. They come in standard series:
- E12 — 12 values in each decade, for ± 10 % parts: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82
- E24 — 24 values, for ± 5 % parts: the E12 values plus 11, 13, 16, 20, 24, 30, 36, 43, 51, 62, 75, 91
- E48 and E96 — 48 and 96 values with three digits, for ± 2 % and ± 1 % parts: 100, 102, 105, 107, 110 …
Each value repeats in every decade: 4.7 Ω, 47 Ω, 470 Ω, 4.7 kΩ, 47 kΩ and so on. In Value → colors you can round your value to a series. For example, 5 kΩ is not a standard value: the nearest is 4.7 kΩ in E12, 5.1 kΩ in E24 and 4.99 kΩ in E96.
SMD resistor codes
| Code | Kind | Value |
|---|---|---|
| 103 | 3 digits: 10 + 3 zeros | 10 kΩ |
| 472 | 3 digits: 47 + 2 zeros | 4.7 kΩ |
| 101 | 3 digits: 10 + 1 zero | 100 Ω |
| 4R7 | R is the decimal point | 4.7 Ω |
| R47 | R is the decimal point | 0.47 Ω |
| 1002 | 4 digits: 100 + 2 zeros | 10 kΩ |
| 4701 | 4 digits: 470 + 1 zero | 4.7 kΩ |
| 01C | EIA-96: value no. 1 (100) × 100 | 10 kΩ |
| 68X | EIA-96: value no. 68 (499) × 0.1 | 49.9 Ω |
| 000 | zero | 0 Ω (a jumper) |
EIA-96 codes are used on very small ± 1 % parts. The two digits are the place in the E96 list, and the letter is the multiplier: Z = 0.001, Y or R = 0.01, X or S = 0.1, A = 1, B or H = 10, C = 100, D = 1,000, E = 10,000, F = 100,000.
Which end is first?
- The tolerance band (gold, silver, or brown on 1 % parts) usually sits a little apart from the others, or is a little wider.
- The first band is closer to the end of the resistor.
- Gold and silver are never the first band.
- Still not sure? Tap Read from the other end. If the turned-around value is not a normal value (not in the E24 list, for example), your first reading was right. When it matters, check with a multimeter.
Frequently asked questions
What is the color code of a 4.7k resistor?
Yellow, Violet, Red, Gold for a 4-band ± 5 % resistor. With 5 bands (± 1 %) it is Yellow, Violet, Black, Brown, Brown.
What are the colors of a 10k resistor?
Brown, Black, Orange, Gold with 4 bands. Brown, Black, Black, Red, Brown with 5 bands.
What does a black first band mean?
Almost always that you are reading from the wrong end. Only a 0 Ω resistor (a wire link) has a single black band.
Why do some resistors have a blue body?
Blue or green bodies are often metal film resistors with 5 bands and ± 1 %. Beige bodies are often carbon film resistors with 4 bands and ± 5 %. This is a habit of the makers, not a rule.
Is grey the same as gray?
Yes. Both spellings mean the same band: 8.
Can I trust the colors in a photo?
Not always. Red, orange and brown look alike under yellow light, and so do blue and violet. When it matters, measure the resistor with a multimeter.
Related tools
- Ohm's Law Calculator — volts, amps, ohms and watts
- LED Resistor Calculator — the resistor value for an LED
- Voltage Divider Calculator — two resistors that make a smaller voltage
- Battery Life Calculator — how long a battery runs your project
- Color Blindness Test — check if red and green look alike to you
How to use it
- Pick Colors → value, Value → colors or SMD code at the top
- Choose 4, 5 or 6 bands
- Tap a band on the drawing (or its button under it), then tap its color — the next band is picked for you
- Read the value, the tolerance and the range in the result
- For the other way, type a value like 4.7k and pick a tolerance and a standard series
- Not sure which end is first? Tap Read from the other end
