Six-band resistor color code calculator with temperature coefficient
Brown-black-black-red-brown-brown is a 10,000 Ω resistor with ±1 % tolerance and a 100 ppm/°C temperature coefficient. Enter the six colors in reading order to get the exact value, tolerance and temperature rating. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Color bands
- brown, black, black, red, brown, brown
- Significant value
- 100
- Multiplier exponent
- 2
- Resistance ohms
- 10000
- Tolerance percent
- 1
A six-band resistor carries more information than the familiar four-band part. The first three colors form its significant value, the fourth scales that value, the fifth states manufacturing tolerance, and the sixth describes temperature coefficient in parts per million per degree Celsius. Enter all six color names in reading order and this calculator returns the exact resistance in ohms, tolerance percentage, and ppm/°C rating without rounding or guessing from a preferred-value series.
Read the six bands in the correct direction
Begin at the end where the colored bands are grouped most closely, leaving the temperature coefficient band last. On a six-band resistor, bands one through three are significant digits. Black represents zero, brown one, red two, and the sequence continues through white for nine.
The fourth band is the multiplier, the fifth is tolerance, and the sixth is temperature coefficient. Orientation matters because the same color can mean a digit, a power-of-ten multiplier, a percentage, or a ppm rating depending on its position. If the physical spacing is difficult to see, look for the tolerance and temperature colors: gold or silver can be a tolerance band but cannot be a significant digit, while common temperature coefficient colors include brown, red, orange, yellow, blue, violet, and grey.
Enter color names from left to right. The calculator accepts either “grey” or “gray,” normalizes capitalization and surrounding spaces, and reports an error when a color is not valid for its particular position rather than silently inventing a value.
Understand resistance and tolerance
The first three bands are joined as a three-digit significant value. For example, brown, black, black produces 100. The multiplier band then applies a decimal power: red means ten squared, so 100 becomes 10,000 ohms.
Gold and silver multipliers support low-value precision resistors by moving the decimal point left one or two places. The returned resistance is an exact decimal string in ohms, which avoids scientific notation and floating-point artifacts. The tolerance band gives the permitted manufacturing deviation around that nominal resistance.
Brown is ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, grey ±0.05%, gold ±5%, and silver ±10%. A 10,000-ohm resistor with a brown tolerance band is therefore specified within one percent of nominal under the conditions stated by its manufacturer. Tolerance is not measurement uncertainty and does not predict every operating effect; self-heating, aging, applied voltage, and circuit conditions can move the observed value.
Use the decoded percentage as a component specification, then consult the part datasheet when a design depends on tighter real-world behavior.
Use the temperature coefficient rating
The sixth band expresses temperature coefficient in parts per million per degree Celsius, commonly written ppm/°C. Brown means 100 ppm/°C, red 50, orange 15, yellow 25, blue 10, violet 5, and grey 1. This rating estimates how strongly resistance changes as component temperature moves away from its reference temperature.
A 10,000-ohm resistor rated at 50 ppm/°C changes by approximately 10,000 × 50 / 1,000,000, or 0.5 ohm, for each degree Celsius of temperature difference. Across 20°C, that first-order estimate becomes 10 ohms. The coefficient may describe a maximum magnitude rather than a guaranteed signed slope, so the color alone does not tell you whether resistance rises or falls.
It also does not replace the manufacturer’s temperature range, drift, power derating, or long-term stability data. The decoded ppm value is particularly useful when comparing parts for precision dividers, instrumentation, references, and sensor interfaces.
What you can do with it
Identify a precision resistor
Decode a loose six-band component before placing it into a repair, prototype, or inventory bin.
Check thermal error budgets
Use the returned ppm/°C rating when estimating resistance drift across an expected temperature change.
Validate a bill of materials
Compare photographed or transcribed band colors with the nominal resistance, tolerance, and temperature coefficient required by a design.
FAQ
What does each band mean?
Bands one through three are digits, band four is the multiplier, band five is tolerance, and band six is temperature coefficient in ppm/°C.
Does the calculator accept gray and grey?
Yes. Both spellings are accepted, and the normalized output uses “grey.”
Why is a color valid in one position but rejected in another?
Each position has its own color table. Gold, for example, can represent a multiplier or tolerance but cannot represent a significant digit or temperature coefficient.
Does ppm/°C show whether resistance increases or decreases?
No. The band gives the coefficient magnitude. Consult the component datasheet for signed behavior and detailed temperature characteristics.
Where do I start reading a six-band resistor?
Begin at the end where the bands sit closest together, so the temperature coefficient band ends up last. Orientation matters, because the same color can stand for a digit, a multiplier, a tolerance or a ppm rating depending on its place.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/elec/resistor-color-6band \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"bands":["brown","black","black","red","brown","brown"]}'const res = await fetch("https://api.kit.forhosting.com/elec/resistor-color-6band", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"bands": [
"brown",
"black",
"black",
"red",
"brown",
"brown"
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/elec/resistor-color-6band",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"bands": [
"brown",
"black",
"black",
"red",
"brown",
"brown"
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/elec/resistor-color-6band", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"bands":["brown","black","black","red","brown","brown"]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"bands":["brown","black","black","red","brown","brown"]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/elec/resistor-color-6band", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"bands": [
"brown",
"black",
"black",
"red",
"brown",
"brown"
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "elec.resistor_color_6band",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Use the temperature coefficient rating
For automated use, the API charges $0.002 per request and returns normalized bands alongside each computed field, making results straightforward to validate and store.
Technical questions
What does API access cost?
Each API request costs $0.002. The browser calculator runs locally for free.