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RMS Calculator

Calculate the root mean square (quadratic mean) of a list of numbers.

RMS

About this calculator

Use this calculator for the quadratic mean of a set: AC voltages and currents, residuals, or any list where you care about magnitude regardless of sign. The RMS of 3 and 4 is √((9 + 16) / 2) = √12.5 ≈ 3.535. For a sine wave, RMS is peak / √2; this page uses the discrete sample formula, not that identity.

The calculation is: rms = √( (x₁² + … + xₙ²) / n ). Separate numbers with commas, semicolons, or spaces. Need at least one number.

Values: Numbers, for example 3, 4.

RMS: Square root of the mean of the squares.