Resistor Color Code Calculator
Pick the color of each band to read the resistance and tolerance, or enter a resistance to see which color bands it needs. Works for 4-band and 5-band resistors.
How to read a resistor color code
- Choose whether your resistor has 4 or 5 bands.
- Select the color of each band from left to right.
- Read off the resistance in ohms and the tolerance percentage.
Examples
4-band resistor
Brown, Black, Red, Gold
1 kohm +-5%
5-band resistor
Brown, Black, Black, Brown, Brown
1 kohm +-1%
Frequently asked questions
How do I read resistor color bands?
On a 4-band resistor the first two bands are digits, the third is a multiplier and the fourth is tolerance. A 5-band resistor adds a third digit band.
What do gold and silver bands mean?
As a multiplier, gold means x0.1 and silver means x0.01. As a tolerance band, gold is +-5% and silver is +-10%.
Which direction do I read the bands?
Read from the end where bands are grouped together. The wider gap before the tolerance band is normally on the right.
What is the digit for each color?
Black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8 and white 9. The same order sets the multiplier powers of ten.
Does it support 5-band precision resistors?
Yes. Select 5 bands to use three significant digits, which is common on 1% precision resistors.
Related tools
LED Resistor Calculator
Calculate the series resistor an LED needs. Enter supply voltage, LED forward voltage and current to get the resistance, nearest E12 value and power.
Ohm's Law Calculator
Solve Ohm's law online. Enter any two of voltage, current, resistance or power and get the other two, with the V, I, R and P formulas shown.
Kinetic Energy Calculator
Calculate kinetic energy, mass or velocity using KE = 1/2 m v^2. Enter any two values in SI units (kg, m/s, joules) to solve for the third.
555 Timer Calculator
Calculate 555 timer astable frequency, period, high and low times and duty cycle from R1, R2 and the timing capacitor. Free oscillator design helper.
Battery Life Calculator
Estimate how long a device runs on a battery from its capacity in mAh and current draw in mA. Includes a real-world efficiency factor for an honest figure.
Bernoulli Equation Calculator
Solve Bernoulli's equation for the downstream pressure from density, upstream pressure, two velocities and two elevations for steady incompressible flow.