Resistor Color Code Calculator
Read a resistor's color bands and get its resistance, tolerance, and
(for 6-band) temperature coefficient. Or do the reverse — type a value
like 4.7 kΩ and see exactly which color bands to look for.
Resistance — Ω
Tolerance —
Min — Max range —
Temp coefficient —
Color code reference
| Color | Digit | Multiplier | Tolerance | Temp coef |
|---|---|---|---|---|
| Black | 0 | ×1 | — | — |
| Brown | 1 | ×10 | ±1% | 100 ppm/K |
| Red | 2 | ×100 | ±2% | 50 ppm/K |
| Orange | 3 | ×1k | — | 15 ppm/K |
| Yellow | 4 | ×10k | — | 25 ppm/K |
| Green | 5 | ×100k | ±0.5% | — |
| Blue | 6 | ×1M | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10M | ±0.1% | 5 ppm/K |
| Grey | 8 | ×100M | ±0.05% | — |
| White | 9 | ×1G | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
How to read which side is band #1
Resistors don't have an arrow telling you which end to read from. Use these rules:
- The tolerance band is offset from the value bands — there's a visible gap. Hold the resistor with the gap on the right.
- Gold or silver is always tolerance (never a digit). If you see gold or silver, that's the last band.
- The first band is usually closer to the lead on modern through-hole resistors.
- If both ends look symmetric, read both directions and pick the one that makes a "common" value (47 Ω, 100 Ω, 220 Ω, 1 kΩ, 4.7 kΩ, 10 kΩ, 100 kΩ, 1 MΩ are the most common). The other reading will be a weird non-standard value.
Common values to memorize
The 9 colors you'll see in 95% of through-hole 1/4 W resistors:
| Bands (4) | Value | Use |
|---|---|---|
| Brown-Black-Brown-Gold | 100 Ω ±5% | LED with 5V (typical for red, drives ~22 mA) |
| Red-Red-Brown-Gold | 220 Ω ±5% | LED with 5V (most common, ~13 mA — safe) |
| Yellow-Violet-Brown-Gold | 470 Ω ±5% | LED with 9V or 12V |
| Brown-Black-Red-Gold | 1 kΩ ±5% | Pull-up / pull-down, basic signal |
| Yellow-Violet-Red-Gold | 4.7 kΩ ±5% | I²C pull-up (with 3.3V or 5V) |
| Brown-Black-Orange-Gold | 10 kΩ ±5% | Most common pull-up (logic, transistor base) |
| Yellow-Violet-Orange-Gold | 47 kΩ ±5% | High-impedance pull-up, low-current bias |
| Brown-Black-Yellow-Gold | 100 kΩ ±5% | RC timing, high-impedance signal |
| Brown-Black-Green-Gold | 1 MΩ ±5% | Op-amp inputs, very high impedance |
Related
- LED Resistor Calculator — figure out which value to use
- Voltage Divider Calculator — pick R1/R2 pairs
- AC Dimmer Power Calculator — for AC switching
- TRIAC Heatsink Sizing — thermal calculations