Free Resistor Color Code Calculator

Determining the exact value of an axial-lead resistor can be confusing without a reference chart. Our free interactive calculator instantly translates standard 4-band, 5-band, and precision 6-band color codes into exact resistance values (Ω, kΩ, MΩ), complete with standard tolerance ranges and temperature coefficients.

How to Read Resistor Color Codes

Resistor color bands are always read from left to right. The bands grouped closely together represent the primary digits and the multiplier, while the single band offset to the right represents the manufacturing tolerance.

• The Digits: The first two bands (or three bands on precision resistors) represent the significant base numbers.
• The Multiplier: The next band determines how many zeros to add to the end of the base numbers (e.g., Orange = x1,000).
• The Tolerance: The offset band shows how much the actual resistance may vary from the stated value (e.g., Gold = ±5%).

How to Use the Calculator

We built this tool to work in two different directions for maximum utility:

• Color to Resistance: Select the number of bands your physical resistor has. Use the dropdowns (or simply click the bands on the graphic above) to match the colors you see on the component. The tool will automatically calculate the SI unit value, the expected minimum/maximum range, and identify the EIA standard series.
• Resistance to Color (Reverse): Need a specific resistor for a breadboard project but don't know what colors to look for? Click the "Resistance to Color" tab, type in your target value (like 4.7 kΩ), and the tool will instantly show you the exact color sequence you need to dig out of your parts bin.

4-Band vs 5-Band vs 6-Band Resistors

Not all resistors are created equal. The number of bands indicates the component's precision level:

• 4-Band Resistors: The most common general-purpose type. Uses 2 significant digits, 1 multiplier, and 1 tolerance band. Usually features Gold (±5%) or Silver (±10%) tolerances.
• 5-Band Resistors: Precision resistors. Uses 3 significant digits, 1 multiplier, and 1 tolerance band. This allows for much finer resistance values and usually features a Brown (±1%) or Red (±2%) tolerance.
• 6-Band Resistors: High-precision and military-spec resistors. Identical to a 5-band, but features a 6th band at the very end that indicates the Temperature Coefficient (how much the resistance shifts as the component heats up).

Tolerance and Temperature Coefficient

No manufacturing process is perfect. Tolerance dictates the maximum allowable error. For example, a 100Ω resistor with a Gold ±5% tolerance will safely measure anywhere between 95Ω and 105Ω. Temperature Coefficient (measured in ppm/°C) is critical for sensitive electronics; a 100 ppm/°C rating means the resistance will shift by 100 parts per million for every single degree Celsius the resistor heats up.

Resistor Color Code Chart

If you prefer to calculate manually, use this standard EIA color reference chart:

Common Resistor Values

Resistors are manufactured in standardized intervals known as E-series. The E12 series (10% tolerance) and E24 series (5% tolerance) are the most common in hobbyist electronics. Some of the most frequently used values in standard circuits include:

• 220 Ω (Red-Red-Brown): Standard LED Current Limiter
• 470 Ω (Yellow-Violet-Brown): General Purpose Pull-down
• 1 kΩ (Brown-Black-Red): Transistor Base Resistor
• 4.7 kΩ (Yellow-Violet-Red): I2C Data Line Pull-up
• 10 kΩ (Brown-Black-Orange): Standard Logic Pull-up/down