Convert RMS voltage to watts for any impedance. Bidirectional: Vrms→W, W→Vrms, Vpeak→Vrms. Shows Vpeak, Vpp, Irms, dBm, and dBW.
The RMS to watts converter calculates electrical power from RMS voltage and impedance using the formula P = V²/R. It supports three modes: Vrms to watts, watts to Vrms, and Vpeak to Vrms to watts — covering every common voltage-to-power conversion scenario.
RMS (Root Mean Square) voltage is the effective voltage of an AC signal that delivers the same power as a DC voltage of the same value. This is the voltage reported by multimeters and used in power calculations for AC circuits.
Results include peak voltage, peak-to-peak voltage, RMS current, dBm, and dBW — essential for audio engineering, RF design, and electrical power analysis. A reference table at the selected impedance shows power for standard voltage levels from 0.1V to 480V. This makes the tool practical for bench testing, system sizing, and troubleshooting overloaded equipment. It is also useful when validating amplifier headroom, selecting safe speaker loads, and comparing datasheet ratings across manufacturers.
Audio engineers, RF technicians, and electricians need to convert between RMS voltage and power for speaker matching, amplifier design, and load calculations. This tool handles all the math for any impedance and helps prevent setup mistakes during equipment matching, commissioning, maintenance checks, and acceptance testing in the field. It keeps calculations repeatable and easier to review.
P = Vrms² ÷ R. Vrms = √(P × R). Vpeak = Vrms × √2. Vpp = 2 × Vpeak. Irms = Vrms ÷ R.
Result: 120 Vrms into 8 Ω = 1,800 W. Vpeak = 169.7 V. Irms = 15 A
P = 120² / 8 = 14,400 / 8 = 1,800 watts. Vpeak = 120 × 1.414 = 169.7 V. Irms = 120 / 8 = 15 A.
Amplifier power ratings should specify RMS watts (continuous power into a specified impedance). "Peak watts" or "PMPO" ratings are marketing inflations. A 100W RMS amplifier into 8Ω delivers 28.3 Vrms. The same 100W into 4Ω needs only 20 Vrms — lower impedance means more current for the same power.
For a pure sine wave, the RMS value is the peak value divided by √2 ≈ 1.414. This factor arises from integrating the square of a sinusoid over one cycle. For non-sinusoidal waveforms (square, triangle, audio music), the relationship between peak and RMS differs.
US: 120 Vrms / 60 Hz. Europe: 230 Vrms / 50 Hz. Japan: 100 Vrms / 50-60 Hz. The peak voltages are much higher: US peak = 170V, EU peak = 325V. Power electronics must handle these peak voltages even though RMS is quoted.
RMS voltage is the effective value of an AC signal — the DC voltage that would deliver the same power to a resistive load. For a sinusoid: Vrms = Vpeak / √2.
P = Vrms² / R, where R is the load resistance in ohms. You must know the impedance to calculate power.
Vpeak is the maximum instantaneous voltage. Vrms = Vpeak / √2 ≈ Vpeak × 0.707. RMS is used for power calculations; peak is used for insulation and component ratings.
P = 120² / 8 = 1,800 watts. This assumes a purely resistive 8-ohm load and ideal operating conditions.
Use the nominal impedance: typically 4Ω, 8Ω, or 16Ω. Actual impedance varies with frequency, but nominal is used for power ratings.
Vpp is the peak-to-peak voltage: the difference between the highest and lowest voltage in one cycle. Vpp = 2 × Vpeak.