Resistor Color Code Calculator
Select the color bands on your resistor:
How to use Resistor Color Code Calculator
1
Enter known values in the input fields provided.
2
Results update instantly as you type — no submit button needed.
3
See the formula box for the equation being applied.
4
All calculations run in your browser — your data is never sent anywhere.
Frequently Asked Questions
How do I read a 4-band resistor? ▼
Bands 1 and 2 are significant digits (0–9). Band 3 is the multiplier (power of 10). Band 4 is tolerance (Gold=±5%, Silver=±10%). Example: Brown-Black-Red-Gold = 1, 0, ×100, ±5% = 1000Ω ±5%.
What is the E24 series? ▼
The E24 series is a set of 24 preferred resistor values per decade, designed so that the maximum error when using a standard value is ≤ 5%. Common values: 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1.
Is this tool free? ▼
Yes, completely free. No signup needed.