Resistor Color Code Calculator
Decode 4-band and 5-band resistor color codes
About the Resistor Color Code Calculator
Resistor color codes are a standardized system for marking resistance values on through-hole resistors using colored bands. The Resistor Color Code Calculator decodes 4-band and 5-band resistor color codes to determine resistance values and tolerance, and can also find the correct color bands for a desired resistance value. It also supports SMD (surface mount device) resistor codes.
Electronics hobbyists identify resistors in circuits, students learn the color code system, and engineers verify component values during PCB assembly. The calculator displays resistance in appropriate units (Ω, kΩ, MΩ) along with the tolerance range showing minimum and maximum acceptable values.
Because calculations run entirely in your browser using JavaScript, you can decode resistor values without any data leaving your device. The visual color display helps you verify the correct band colors against actual components.
How to Use the Resistor Color Code Calculator
- Select the resistor mode from the dropdown: 4-band, 5-band, or SMD code.
- For band resistors, choose the color for each band from the color dropdown menus in order from left to right.
- For SMD resistors, enter the 3 or 4-digit code printed on the component.
- Click Calculate to determine the resistance value.
- View the resistance in ohms, kilohms, or megohms along with the tolerance range.
- Copy the results to your clipboard for documentation or reference.
Why Use ToolForge’s Resistor Color Code Calculator
- Decoding runs fully client-side, so the tool keeps working without an internet connection and nothing about your components is ever transmitted.
- Supports 4-band, 5-band, and SMD resistor codes in one tool, covering most resistor types encountered in electronics work.
- Displays resistance in appropriate units (Ω, kΩ, MΩ) automatically based on the calculated value.
- Shows the tolerance range (minimum and maximum values) to understand the acceptable variation in resistance.
Frequently Asked Questions
How do I read resistor color codes?
For 4-band resistors: the first two bands are significant digits, the third is the multiplier, and the fourth is tolerance. For 5-band resistors: the first three bands are significant digits, the fourth is the multiplier, and the fifth is tolerance. Read bands from left to right, with the tolerance band (usually gold or silver) on the right.
What are the standard resistor color codes?
Standard digit color codes are: Black(0), Brown(1), Red(2), Orange(3), Yellow(4), Green(5), Blue(6), Violet(7), Grey(8), White(9). Multipliers include Black(×1), Brown(×10), Red(×100), Orange(×1K), Yellow(×10K), Green(×100K), Blue(×1M), Violet(×10M), Gold(×0.1), Silver(×0.01).
What tolerance values are available?
Standard tolerance color codes are: Brown(±1%), Red(±2%), Green(±0.5%), Blue(±0.25%), Violet(±0.1%), Grey(±0.05%), Gold(±5%), Silver(±10%). Tolerance indicates the maximum deviation from the marked resistance value.
Does this calculator support SMD resistors?
Yes, the calculator supports SMD (surface mount device) resistor codes. For 3-digit codes, the first two digits are significant and the third is the multiplier. For 4-digit codes, the first three are significant and the fourth is the multiplier. An 'R' indicates a decimal point.
How do I find colors for a desired resistance?
Enter the desired resistance value and tolerance, then use the calculator in reverse mode to find the correct color bands. This is useful when you need to find a resistor with specific characteristics in your inventory.
