MAXScanner engineering calculator
Updated 2026-09-18
RMS Voltage Calculator — Waveform, Peak, DC Offset & Crest Factor
Convert peak AC voltage to RMS for sine, square, triangle, sawtooth and rectified waveforms, then combine an independent DC offset by root-sum-square. See AC RMS, total RMS, peak-to-peak and crest factor.
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- 1.RMS factor: Sine = 0.707107; Peak AC magnitude = 325 V.
- 2.AC waveform RMS: Vpeak × factor = 325 × 0.707107 = 229.81 V.
- 3.Total RMS voltage: √(AC RMS² + DC²) = √(229.81² + 0²) = 229.81 V.
- 4.Peak-to-peak AC: 2 × Vpeak = 2 × 325 = 650 V; AC crest factor = 1 ÷ 0.707107 = 1.41421.
Formula, example and limits
AC RMS: sine Vp/√2; square Vp; triangle/sawtooth Vp/√3; half-wave sine Vp/2. With independent DC offset V0: Vrms,total = √(Vrms,AC² + V0²).
325 V peak sine with 0 V DC offset is about 229.8 V RMS and 650 V peak-to-peak. Adding DC offset increases total RMS by root-sum-square, not ordinary addition.
- Waveform formulas use ideal periodic shapes and the entered AC peak magnitude.
- The DC-offset combination assumes the entered offset is the waveform mean; distortion, clipping, harmonics or time-varying bias require RMS integration or measurement of the actual waveform.
Frequently asked questions
Why is RMS lower than peak for a sine wave?
RMS represents equivalent heating power over the cycle; a sine spends most of its time below its peak.
How does DC offset change RMS voltage?
For an AC component with zero mean plus a constant DC offset, total RMS is the square root of AC RMS squared plus DC offset squared. The two values are not simply added.
Is peak-to-peak always twice peak?
For the AC excursion of a symmetric waveform, yes. A DC offset shifts both extrema by the same amount, so it does not change that AC peak-to-peak span.
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