Do you want to read a resistor value from its color bands or SMD code, or generate the bands and codes from a resistance value in ohms? This universal calculator supports THT and SMD resistors, EIA-96 codes, and standard E series.
Universal THT and SMD resistor calculator
Select the resistor type and use the desired section. THT resistors, or Through-Hole Technology resistors, are traditional components with leads that pass through holes in the printed circuit board; SMD resistors, or Surface-Mount Device resistors, are soldered directly onto the board surface. For numeric values, you can use either a comma or a period as the decimal separator. Do not use thousands separators.
THT resistor: color bands to value
Select the number of bands, then click a resistor band and choose its color. A 3-band resistor uses an implicit 20% tolerance.
Select all required colors to obtain the result.
THT resistor: value to color bands
Enter the value and select the number of bands. The calculator generates the bands only when the value can be represented exactly by the selected color code.
The value can be represented exactly with the selected number of bands.
The value cannot be represented exactly with the selected number of bands. Try a different number of bands or a standard value.
Enter a valid positive numeric value.
SMD resistor: code to value
Enter the code printed on the component. You can select the format or use automatic detection.
The entered code is not valid for the selected format.
SMD resistor: value to code
Select the desired format and enter the value. The calculator returns a code only if the value can be represented exactly in the selected format.
The value can be represented exactly in the selected format.
The value cannot be represented exactly in the selected format. For low values, try R notation; for EIA-96, use values from the E96 series.
Enter a valid non-negative numeric value.
Standard E series
Enter a value and select a series. The calculator shows the previous standard value, the nearest standard value, and the next standard value.
The entered value is an exact value in the selected series.
The entered value is not an exact value in the selected series.
Enter a valid positive numeric value.
How to read THT resistor color bands
Axial THT resistors indicate their value with color bands. In 3- and 4-band codes, the first two bands represent the significant digits and the next band is the multiplier. In 5- and 6-band codes, there are three significant digits.
A 3-band resistor has no dedicated tolerance band and normally indicates a 20% tolerance. In 4- and 5-band codes, the last band indicates tolerance, while a 6-band code also includes the temperature coefficient, or TCR.
Resistor color code table
| Color | Digit | Multiplier | Tolerance | TCR |
|---|---|---|---|---|
| Black | 0 | 1 | ||
| Brown | 1 | 10 | 1% | 100 ppm/°C |
| Red | 2 | 100 | 2% | 50 ppm/°C |
| Orange | 3 | 1,000 | 15 ppm/°C | |
| Yellow | 4 | 10,000 | 25 ppm/°C | |
| Green | 5 | 100,000 | 0.5% | |
| Blue | 6 | 1,000,000 | 0.25% | 10 ppm/°C |
| Violet | 7 | 10,000,000 | 0.1% | 5 ppm/°C |
| Gray | 8 | 100,000,000 | 0.05% | |
| White | 9 | 1,000,000,000 | ||
| Gold | 0.1 | 5% | ||
| Silver | 0.01 | 10% |
The TCR values available in the calculator follow the most common combinations shown in technical reference tables. Some manufacturers may use additional coding schemes or product-specific conventions.
SMD resistor codes
SMD resistors may use numeric or alphanumeric codes. A 3-digit code uses two significant digits and a multiplier, while a 4-digit code uses three significant digits and a multiplier.
For low resistance values, R notation is common: the letter R replaces the decimal point. The EIA-96 system uses two digits to identify one of the 96 values in the E96 series and a letter to indicate the multiplier.
| SMD code | Format | Value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 472 | 3 digits | 4.7 kΩ | |||||||
| 4701 | 4 digits | 4.7 kΩ | |||||||
| 4R7 | R notation | 4.7 Ω | |||||||
| R47 | R notation | 0.47 Ω | |||||||
| 01A | EIA-96 | 100 Ω | |||||||
| 25C | EIA-96 | 17.8 kΩ | |||||||
| 93D | EIA-96 | 909 kΩ | |||||||
Codes such as 1206, 0805, 0603, 0402, and 0201 may indicate the physical component size rather than the resistance value. In addition, smaller SMD components may have no marking.
Standard E12, E24, E48, E96, and E192 series
The E series define sets of preferred values distributed across each decade. E12 and E24 are common for resistors with wider tolerances, while E48, E96, and E192 provide more closely spaced values and are typical of precision resistors.
The standard E series section compares the entered value with the selected series. This lets you check whether the exact value exists and identify the previous, nearest, and next standard values.
Limitations and special cases
The calculator uses the most common standard coding systems. Proprietary markings, special resistors, fusible resistors, resistor networks, and manufacturer-specific codes may follow different conventions.
Zero-ohm resistors used as jumpers are a special case. The calculator recognizes the numeric SMD codes 000 and 0000 and R notation 0R0, but does not generate a single-band THT code.