Resistor Color Code Calculator
Decode 4-band resistors from colors — and reverse value → colors.
See how it works
Watch a quick simulation of this tool in action — no file needed.
How to use Resistor Color Code Calculator
Follow these steps — everything happens instantly in your browser.
- 1
Step 1. Set the four bands (1st digit, 2nd digit, multiplier, tolerance) using the dropdowns.
- 2
Step 2. See the resistance value and tolerance range update instantly.
- 3
Step 3. Switch to reverse mode to convert a value back into band colors.
Why use this tool
Private by design
All processing happens locally in your browser. Open DevTools → Network and you'll see zero file uploads. Ever.
Instant
No upload wait, no queue, no server round-trip. Results appear the moment you drop a file.
Free & unlimited
No accounts, no watermarks, no daily caps. Use it as many times as you like, forever.
Works everywhere
Desktop, tablet or phone — every tool is responsive and installable as a PWA for offline use.
Frequently asked questions
Everything you might want to know about resistor color code calculator.
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