Root Mean Square Calculator RMS of values. a b c RMS 4.082 Step-by-step with your numbers: 1. Values used: 2. a = 3 3. b = 4 4. c = 5 5. RMS = 4.082 Did we solve your problem today? 👍 Yes 👎 No Thanks for the feedback! RMS = √(Σx²÷n). FAQ Use? AC voltage, statistics. Related calculators Average (Mean) Calculator Find the arithmetic mean of up to five numbers. Geometric Mean Calculator Find the geometric mean of a set of positive numbers. Harmonic Mean Calculator Find the harmonic mean of up to three numbers.