Resistor Color Code Calculator

Use this resistor color code calculator to instantly decode the resistance value from the color bands printed on any through-hole resistor.

Resistor Color Code Table

Each color corresponds to a digit, a multiplier, a tolerance, and (on 6-band resistors) a temperature coefficient:

Band Configurations

4-Band Resistors (Most Common)

Example — Yellow, Violet, Red, Gold:

• Yellow = 4, Violet = 7 → significant digits: 47
• Red = ×100 Ω → 47 × 100 = 4,700 Ω = 4.7 kΩ
• Gold = ±5% tolerance

5-Band Resistors (Precision ±1%)

Example — Red, Red, Black, Brown, Brown:

• Red = 2, Red = 2, Black = 0 → significant digits: 220
• Brown = ×10 Ω → 220 × 10 = 2,200 Ω = 2.2 kΩ
• Brown = ±1% tolerance

6-Band Resistors (Precision + Temp. Coefficient)

Identical to 5-band, with a 6th band indicating the temperature coefficient:

• Brown (100 ppm/°C) — standard precision
• Red (50 ppm/°C) — military grade
• Orange (15 ppm/°C) — high stability

How to Read a Resistor: Step by Step

1. Orient the resistor — Hold it so the tolerance band (gold or silver) is on the right. The left side starts with the first significant digit.
2. Identify the number of bands — Count them. Most common hobby resistors have 4 bands; precision resistors have 5.
3. Read the significant digits — Look up each color in the table above.
4. Apply the multiplier — Multiply the digit number by the multiplier value.
5. Note the tolerance — This tells you how far the actual resistance may vary from the labeled value.

Tip: If you are unsure which end to start from, measure the resistance with a multimeter to confirm.

Common Resistor Values and Their Color Codes

What Are Resistors?

Resistors are passive components that oppose the flow of electric current. They are vital in electronic circuits because they:

• Limit current to protect LEDs, transistors, and ICs from overcurrent damage
• Divide voltage when connected in series (see the voltage divider calculator)
• Set bias points for transistors and op-amps
• Create time constants with capacitors (RC circuits) and inductors (RL circuits)

The most common resistors you'll use in hobbyist projects are 1/4W carbon film (±5%, 4-band) and 1/4W metal film (±1%, 5-band) resistors.

Power Rating

Resistors are also rated by the maximum power they can dissipate as heat ($P = V \times I = I^2 R = V^2/R$):

Frequently Asked Questions

How do I tell which end of the resistor to start reading from?

The tolerance band (gold or silver) is always the last band — place it on the right. The color bands are not always symmetrically spaced, so look for a wider gap between the tolerance band and the rest. When in doubt, measure with a multimeter and match the reading to a plausible color code.

What does a resistor with no color bands mean?

A completely unmarked resistor (or one marked with a single black band) is a 0 Ω jumper — a wire replacement used to bridge PCB traces. This is different from a short circuit: it's an intentional design choice to enable board rework or programming options without rewiring.

My resistor has only 3 bands — is that normal?

Yes. Some older or very cheap resistors use a 3-band system: two significant digits + multiplier, with an implied ±20% tolerance. Three-band resistors are rare in modern components but still appear in old equipment.

Can I always trust the color code?

Color bands can be misleading if the resistor is old, discolored by heat, or if the colors are ambiguous (orange vs. red, brown vs. maroon). Always verify with a multimeter if accuracy matters — tolerance alone means a "10 kΩ" resistor at ±5% can be anywhere from 9.5 kΩ to 10.5 kΩ.