Wirecora resistor guide
Resistor Tolerance Explained with Practical Ranges
Learn what resistor tolerance means, how to calculate minimum and maximum resistance, and why tolerance is not the same as accuracy in every condition.
Direct answer: Resistor tolerance is the permitted percentage difference between nominal and actual resistance at specified reference conditions. It defines a range, not a promise that every part sits at the center value.
Band-by-band explanation
- Band 1 · First digitBrown
- Band 2 · Second digitBlack
- Band 3 · MultiplierRed
- Band 4 · ToleranceGold
The Gold tolerance band is read at the right-hand end.
How it works
- Convert the tolerance percentage to a decimal by dividing it by 100.
- Multiply nominal resistance by that decimal to find the allowed deviation.
- Subtract and add the deviation to obtain the minimum and maximum resistance values.
Practical example
For a 1 kΩ ±5% resistor, the deviation is 1,000 × 0.05 = 50 Ω. Its specified tolerance range is therefore 950 Ω to 1,050 Ω at the applicable reference conditions.
Common mistakes
Check these points before relying on a color-code reading or component substitution.
Do not treat tolerance as the total width of the range; ±5% extends five percent below and five percent above nominal.
Do not assume tolerance includes every temperature, aging, voltage, and measurement effect unless the datasheet says so.
Related resistor values
Open a worked color-code page generated from the same resistor engine as the calculator.
Related guides
How to Read a 4-Band Resistor Color Code
Read a 4-band resistor by identifying its first two digits, multiplier, and tolerance, with a complete 220 ohm worked example.
Resistor Temperature Coefficient Explained
Learn how resistor TCR in ppm/K estimates resistance change with temperature and how the sixth color band differs from ordinary tolerance.
Frequently asked questions
Short answers to questions that commonly arise with this resistor topic.
Is a 1% resistor always exactly 1% away from nominal?
No. Its measured value may be anywhere inside the allowed band, including very close to nominal.
Does tighter tolerance always mean lower noise?
No. Tolerance, noise, temperature stability, voltage coefficient, and construction are separate specifications.
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