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Enter your values, then click Calculate result.How this calculator helps
Decode four- or five-band resistor colors into nominal ohms and tolerance limits using an explicit digit and multiplier convention. Identify the tolerance band and read the significant digits from the opposite end according to the component marking. Band spacing can help, but the calculator cannot inspect a photograph or distinguish faded colors. Select four or five bands before entering their meanings. A wrong reading direction or count can produce a plausible number that describes a different resistor, so confirm the actual component markings first.
How to use it
- 1
Select the correct input roles for resistor color code calculator and enter the values described below. The demonstration defaults illustrate the method; they are not independently verified personal measurements or live market data.
- 2
Review digits and multiplier and the original source record. Match units, signs and the chosen mode before submitting, rather than relying on a familiar-looking default number.
- 3
Click Calculate result to submit the current fields. Editing an input preserves the prior submitted output until you calculate again; the pending-change message distinguishes that saved output from the new values.
- 4
Check the labeled output against the worked example and independent verification steps. Review supported markings before using the result in another document, and keep the complete input basis with a copied answer.
Formula and methodology
Four bands: (10d₁+d₂)×10ᵐ Ω. Five bands: (100d₁+10d₂+d₃)×10ᵐ Ω. Tolerance limits = nominal×(1±t/100).
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
Choose four bands, yellow then violet, red multiplier and gold tolerance. The digits form 47 and red multiplies by 100, giving 4700 Ω with ±5% tolerance. The modeled endpoints are 4465 Ω and 4935 Ω. The third-digit selector is ignored in four-band mode; it only adds another significant digit in five-band mode.
How to interpret your result
The tolerance band supplies a percentage around the nominal value. Gold means ±5% and silver ±10%; the selector includes several tighter marked tolerances. A missing tolerance band can be represented with the four-band convention of 20%, while five-band mode requires a marked tolerance. The endpoints are calculated by multiplying nominal ohms by one minus or plus the percentage, not by adding that number of ohms.
For different inputs or formulas, use Parallel Resistor Calculator; Ohm’s Law, Watt and Ampere Calculator; RC Filter Calculator.
Related questions this calculator covers
- resistor calculator
- electronic color code calculator
- resistor color code calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| Four bands | brown, black, red, gold gives 1000 Ω ±5%. |
| Five bands | red, orange, violet, black, brown gives 237 Ω ±1%. |
| Fractional multiplier | brown, black, gold gives nominal 1 Ω. |
Common mistakes to avoid
- Treating the multiplier color as another digit.
- Using the same color meaning for multiplier and tolerance positions.
- Inferring wattage or safe operating voltage from resistance bands.
Write the two or three significant digits, multiply by the selected factor and calculate both percentage endpoints manually. Check the manufacturer chart rather than a color name guessed from a photo. Compare a known four-band and five-band example. An isolated meter measurement is a separate verification step and must account for measurement accuracy.
Authoritative reference. Method and scope reviewed on 5 October 2026. SolvePilot provides the original worked example and bounded browser implementation. Editorial and arithmetic review by Mohammad Qasim does not certify user measurements, a real contract or an individual professional decision. The reference supplies method, unit or source-record context; it does not approve this implementation or its inputs.What can affect the result?
Reading direction
Identify the tolerance band and read the significant digits from the opposite end according to the component marking. Band spacing can help, but the calculator cannot inspect a photograph or distinguish faded colors. Select four or five bands before entering their meanings. A wrong reading direction or count can produce a plausible number that describes a different resistor, so confirm the actual component markings first.
Digits and multiplier
Black through white encode digits zero through nine. The first significant digit cannot be black in this worksheet. Four-band mode uses two significant digits and five-band mode uses three. The multiplier is separate from those digits: red means a factor of one hundred, gold one tenth and silver one hundredth. A gold multiplier changes nominal resistance; it does not imply gold tolerance unless that separate band is also selected.
Tolerance interval
The tolerance band supplies a percentage around the nominal value. Gold means ±5% and silver ±10%; the selector includes several tighter marked tolerances. A missing tolerance band can be represented with the four-band convention of 20%, while five-band mode requires a marked tolerance. The endpoints are calculated by multiplying nominal ohms by one minus or plus the percentage, not by adding that number of ohms.
Compare a measurement
A meter reading can be compared with the nominal interval, but the measurement setup matters. An in-circuit measurement can include other paths and therefore need not reflect the isolated resistor. Temperature, meter accuracy and physical condition also affect readings. This page decodes supplied colors; it does not identify a burned component, certify a marking or establish whether a circuit is safe to energize.
Supported markings
Six-band temperature coefficients, surface-mount numeric codes, special-purpose markings and zero-ohm jumpers are outside this decoder. It does not infer wattage, maximum working voltage or a component package from resistance colors. Nominal ohms and tolerance alone do not select a replacement part. Use the manufacturer data for the physical component, and retain the full color sequence alongside any copied result.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Six-band temperature coefficients, surface-mount numeric codes, special-purpose markings and zero-ohm jumpers are outside this decoder. It does not infer wattage, maximum working voltage or a component package from resistance colors. Nominal ohms and tolerance alone do not select a replacement part. Use the manufacturer data for the physical component, and retain the full color sequence alongside any copied result.
Sources and review information
Frequently asked questions
What changes with five bands?＋
There are three significant digit bands instead of two. The multiplier and tolerance remain separate, and the third digit must be supplied.
Is gold always 5%?＋
Only in the tolerance position. In the multiplier position gold means multiplication by 0.1.
Can the first band be black?＋
This decoder rejects a leading zero digit. It does not interpret a zero-ohm jumper as an ordinary four- or five-band resistor.
Does the output show power rating?＋
No. Resistance colors do not establish the power rating or voltage limit of the component.
Can I decode a six-band resistor?＋
Not completely here. The additional temperature-coefficient band requires a separate manufacturer-supported interpretation.