Chip Resistor Code Calculator

Calculator

Use decode mode to read a printed marking. Use encode mode to generate common resistor codes from a resistance value.

Mode

Chip Code

Code Family / Preferred Output

Resistance Value

Resistance Unit

Tolerance (%)

TCR (ppm/°C)

Temperature Change (°C)

Package Size

Example Data Table

Printed Code	Family	Decoded Value	Explanation
472	3-digit	4.7 kΩ	47 × 10² = 4700 Ω
1001	4-digit	1 kΩ	100 × 10¹ = 1000 Ω
4R7	R marking	4.7 Ω	R replaces the decimal point.
1K0	K marking	1 kΩ	K replaces the decimal point and sets kilo-ohms.
01A	EIA-96	100 Ω	E96 index 01 gives 100. A means ×1.
000	Zero-ohm	0 Ω	Used as a jumper link on many boards.

Formula Used

3-digit code: R = (10a + b) × 10^c Ω

4-digit code: R = (100a + 10b + c) × 10^d Ω

EIA-96 code: R = E96 base value × multiplier letter factor

R/K/M marking: The letter acts as a decimal point and a magnitude symbol.

Tolerance window: R_min = R × (1 − t), R_max = R × (1 + t)

Temperature estimate: R_T = R × [1 + (TCR × ΔT / 1,000,000)]

How to Use This Calculator

Select Decode marking when you have a printed code such as 472, 1001, 4R7, or 01A.
Select the code family manually or leave it on Auto for detection.
Select Encode resistance when you want markings for a known resistor value.
Enter tolerance, TCR, and temperature change to estimate operating limits.
Press Submit to show the result above the form.
Review the graph, alternative markings, and export buttons for reporting.

FAQs

1. What does a 3-digit resistor code mean?

The first two digits are the significant value. The last digit is the multiplier power of ten. For example, 472 becomes 47 × 10², which equals 4700 ohms.

2. What does a 4-digit resistor code mean?

A 4-digit code uses the first three digits as the significant value and the last digit as the multiplier. This gives finer resolution than the 3-digit scheme.

3. What is EIA-96 marking?

EIA-96 is a compact system often used on 1% resistors. Two digits point to an E96 base value, and one letter applies the multiplier.

4. What does the letter R mean in a code?

R replaces the decimal point and keeps the value in ohms. A code such as 4R7 means 4.7 ohms, while 0R22 means 0.22 ohms.

5. Why do some resistors show 000?

Codes like 0, 00, 000, or 0000 usually indicate a zero-ohm jumper. These parts behave like short links for routing and configuration.

6. Does package size change the code value?

No. Package size affects physical dimensions, power handling, and thermal behavior. The marking still represents the nominal resistance code family and value.

7. Why is tolerance important here?

Tolerance shows the possible spread around the nominal resistance. It helps you estimate minimum and maximum values, which matters in precision designs.

8. Why does the calculator include TCR?

TCR estimates how resistance may shift with temperature. It is useful when you need a quick operating-value estimate beyond the nominal room-temperature marking.