Resistor Calculator
Calculate resistor values from color bands or determine the color bands from a given resistance value and tolerance.
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator converts resistor color bands to resistance values and vice versa. Follow the steps below for each mode.
Mode 1: Color to Value
- Select Band 1 and Band 2 – Choose the colors for the first two significant digits.
- Select Multiplier – Choose the color that sets the decimal multiplier (e.g., Red = ×100).
- Select Tolerance – Choose the color indicating the tolerance percentage.
- Click "Calculate" – The resistance value (in Ω, kΩ, or MΩ) and tolerance will appear below.
Mode 2: Value to Color
- Enter Resistance – Type a positive number in ohms (e.g., 4700 for 4.7 kΩ).
- Select Tolerance – Choose the desired tolerance percentage.
- Click "Get Colors" – The corresponding 4-band color code is displayed with colored bands and text labels.
Note: The calculator uses standard 4-band resistor coding. All inputs must be valid; errors will show in red. Results update instantly after each calculation.
Previous Results
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Frequently Asked Questions
The first two bands represent the first two digits of the resistance value, the third band is the multiplier, and the fourth band indicates tolerance. For example, red (2), red (2), orange (×1000) gives 22,000 Ω or 22 kΩ with a typical gold tolerance of ±5%.
Tolerance indicates how much the actual resistance can vary from the stated value. Common tolerances are ±5% (gold), ±10% (silver), and ±1% (brown). Lower tolerance means higher precision.
Currently, this calculator supports 4-band resistors. For 5-band resistors, the first three bands are significant digits, the fourth is multiplier, and fifth is tolerance. A future update may add this feature.