brown, black, red, gold
- Tolerance
- +/- 5%
- Minimum
- 950 ohms
- Maximum
- 1050 ohms
Resistor Calculator
Use this free resistor calculator to convert common 4-band color codes into resistance, tolerance percentage, minimum ohms, and maximum ohms.
Inputs explainedResult checksExample valuesRuns in your browser
Formula steps
- Read the first two color bands as digits.
- Multiply by the multiplier color band.
- Read the tolerance band as the expected manufacturing range.
Examples
Recent answers
Recent resistor color decodes will appear here.
Resistor color decoding is local and for component identification, not live circuit testing.
Inputs and recent answers stay in this browser tab and are not sent to a server.
How to use the Resistor Calculator
- Choose the first digit, second digit, multiplier, and tolerance color bands.
- Press Decode resistor to see ohms and the tolerance range.
- Read bands in the correct direction before trusting the answer.
- Use a multimeter for real parts when circuit behavior matters.
What people use it for
Decode a common 4-band resistor before placing it on a breadboard.
See the tolerance range around the nominal resistance.
Check whether a 220 ohm, 1 kOhm, 4.7 kOhm, 10 kOhm, or 47 kOhm example looks right.
Compare resistor values before using Ohm's law.
Turn faded color-band notes into an ohm range before checking with a multimeter.
Explain color-code homework without skipping the tolerance math.
Quick examples
1 kOhm
brown black red gold1,000 ohms +/- 5% (950 to 1,050 ohms)
4.7 kOhm
yellow violet red gold4,700 ohms +/- 5% (4,465 to 4,935 ohms)
220 ohm
red red brown gold220 ohms +/- 5% (209 to 231 ohms)
10 kOhm
brown black orange gold10,000 ohms +/- 5% (9,500 to 10,500 ohms)
330 ohm
orange orange brown gold330 ohms +/- 5% (313.5 to 346.5 ohms)
47 kOhm
yellow violet orange gold47,000 ohms +/- 5% (44,650 to 49,350 ohms)
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Resistor CalculatorSee slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- CalculatorsBrowse related calculators and utilities in the same category.
- Electrical Calculator HubCompare this with the nearby tools and checks in the same job path.
- Calculator and utility guidesFind more guides that use real tool inputs and example numbers.
- All free toolsSearch every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.
When should I use the Resistor Calculator?
Use it when your task matches one of these common needs: Decode a common 4-band resistor before placing it on a breadboard. See the tolerance range around the nominal resistance. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Resistor Calculator doing with my inputs?
In plain language: Read the first two bands as digits, multiply by the third band, then apply the fourth band tolerance to get the minimum and maximum possible resistance. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Resistor Calculator inputs mean?
First digit band: the first significant digit printed on a common 4-band resistor. Second digit band: the second significant digit before the multiplier is applied. Multiplier band: the scale factor that turns the two digits into ohms, including gold or silver for fractional multipliers. Tolerance band: the expected manufacturing range around the nominal resistance, such as gold for +/- 5%.
How should I read the Resistor Calculator answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
What should I double-check before trusting the answer?
This is for common 4-band color-code math. Use a multimeter and proper circuit safety for real parts, especially when bands are faded, damaged, or hard to read. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
What does resistor tolerance mean?
Tolerance says how far the real part may be from the printed value. A 1,000 ohm resistor with +/- 5% tolerance may be anywhere from about 950 to 1,050 ohms and still match its rating.
Which end of the resistor should I read first?
Start from the end with the color bands grouped closer together, then read toward the tolerance band. The tolerance band is often gold or silver and usually sits slightly separated from the first three bands.
Does this calculator support 5-band resistors?
No. This page is for common 4-band resistors with two digit bands, one multiplier band, and one tolerance band. A 5-band resistor uses three digit bands and needs a different decode pattern.
Can gold and silver be multiplier bands?
Yes. Gold as a multiplier means x0.1 and silver means x0.01. Gold and silver are also common tolerance bands, so use the band position, not only the color, when reading the part.
Why should I still check with a multimeter?
Color bands can fade, smear, or be read backward. A multimeter confirms the real resistance before you use the part in a circuit where the exact value matters.
Can I use this result on a powered circuit?
Do not measure or swap resistors on a powered circuit unless you are trained and the circuit is made safe. The calculator explains the code on the part; it does not replace electrical safety checks.
Does the site save what I enter?
No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.