Enter the nominal resistance value and the percentage tolerance into the calculator to determine the tolerance of the resistor. This calculator can also evaluate any of the variables given the others are known.

Resistor Tolerance Formula

The following formula is used to calculate the tolerance of a resistor.

T = (R * P) / 100


  • T is the tolerance of the resistor (Ohms) R is the nominal resistance value (Ohms) P is the percentage tolerance (%)

To calculate the tolerance of a resistor, multiply the nominal resistance value by the percentage tolerance, then divide the result by 100. The result is the tolerance of the resistor in Ohms.

What is a Resistor Tolerance?

Resistor tolerance is a specification that indicates the range within which the actual resistance of a resistor will deviate from its nominal or stated resistance. It is usually expressed as a percentage. For example, a resistor with a nominal value of 100 ohms and a tolerance of 10% could have an actual resistance anywhere between 90 and 110 ohms. The tolerance is a measure of the resistor’s precision, with lower tolerance values indicating higher precision.

How to Calculate Resistor Tolerance?

The following steps outline how to calculate the Resistor Tolerance.

  1. First, determine the nominal resistance value (R) in Ohms.
  2. Next, determine the percentage tolerance (P) in %.
  3. Next, gather the formula from above = T = (R * P) / 100.
  4. Finally, calculate the Resistor Tolerance.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

nominal resistance value (R) = 100 Ohms

percentage tolerance (P) = 5%