Média quadrática (RMS) 2 valores
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The RMS (root mean square) calculator for 2 values computes the square root of the average of squared numbers. The formula used is √((a² + b²)/2), where a and b are the input values. This type of average is widely used in electrical engineering, physics, and statistics to represent the magnitude of variable quantities, such as AC voltages or sound waves.
To use the calculator, simply enter two real numbers. The calculation first squares each number, sums the results, divides by two to find the average of squares, and finally takes the square root. For example: with values 3 and 4, the RMS is √((9 + 16)/2) = √12.5 ≈ 3.54. This method is ideal when the total magnitude of the values is more relevant than the arithmetic mean.
Note that the RMS will always be greater than or equal to the geometric mean and arithmetic mean of the same values. Negative numbers are correctly handled since squaring eliminates the sign. Common applications include power calculations in AC circuits, signal noise analysis, and materials engineering. Always check the input units for consistency in results.
Frequently asked questions
What is the difference between RMS and arithmetic mean?
RMS squares the values before averaging, while arithmetic mean sums them directly. RMS emphasizes extreme values and is used for absolute magnitudes, such as in AC current calculations.
What is RMS used for?
It's used in electrical engineering to calculate effective voltages in AC circuits, in signal analysis, and in materials engineering to measure stresses and deformations.
Can I use negative numbers in the calculator?
Yes, since squaring removes the negative sign. The result will always be positive, representing the magnitude of the input values.
Is RMS the same as standard deviation?
No, standard deviation measures dispersion around the mean, while RMS represents the average magnitude of values without referencing the mean.