Voltage Converter
Convert volts, millivolts, kilovolts and microvolts, with dBu and dBV handled as the logarithmic references they are — not as extra rows in a unit list.
Voltage Converter
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- RMS to peak conversion assumes a pure sine wave; square, triangular and distorted waveforms have different crest factors.
- The Ohm's law card is a cross-check on a purely resistive load and ignores reactance, power factor and frequency effects.
- Voltage bands are orientation only and are not a safety assessment. No figure on this page should be relied on when working on live equipment.
In short: Voltage converts through the volt, one joule per coulomb. The SI prefixes are exact powers of ten, so 1 kV is 1,000 V and 1 mV is 0.001 V. The audio references dBu and dBV are shown separately because they are logarithmic, not linear: 0 dBu is 0.7745966692 V and 0 dBV is exactly 1 V, which is why the two scales sit 2.2185 dB apart.
Formula
Each factor is the number of volts in one of that unit. The SI prefixes are exact powers of ten. The decibel formulae are shown separately because they are logarithmic and cannot be expressed as a multiplying factor.
Worked Example
- Identify the source factor. One volt is 1.
- Convert to the SI unit. 230 × 1 = 230 V.
- Identify the target factor. One millivolt is 0.001 V.
- Divide. 230 ÷ 0.001 = 230,000 mV.
- Treat decibels separately. 230 V is about 49.5 dBu — obtained by a logarithm, not by multiplication.
Why 0 dBu is 0.7746 volts. Telephone and broadcast lines were once terminated in 600 ohms, and the reference level was one milliwatt into that load. Since P = V²/R, the voltage that dissipates 1 mW into 600 Ω is the square root of 0.001 × 600, or 0.7745966692 V. The 600-ohm convention is long gone but the odd reference voltage survived, which is why professional audio runs at +4 dBu (1.2277 V) while consumer gear runs at −10 dBV (0.3162 V) — a real gap of 11.78 dB, not the 14 dB that subtracting the labels would suggest.
Strengths & Limits Of This Model
Where this engine is strong
- Keeps dBu and dBV as clearly labelled logarithmic references instead of smuggling them into the unit list.
- Derives the 0 dBu reference from one milliwatt into 600 ohms rather than hard-coding 0.775.
- Shows RMS, peak and peak-to-peak together, which is where most insulation and rating errors begin.
Where it stops
- Does not model AC power factor or reactance.
- Crest factor assumes a sinusoid.
- Not a voltage-drop or circuit design calculator.
Practical Use Cases
Instrumentation and sensor work
Thermocouples, strain gauges and biopotential electrodes produce outputs in microvolts and millivolts, while data acquisition systems are specified in volts.
Audio engineering and gain staging
Professional equipment operates at +4 dBu and consumer equipment at −10 dBV. Knowing the true 11.78 dB gap between them prevents both clipping and buried noise floors.
Power distribution and transmission
Distribution runs from hundreds of volts to hundreds of kilovolts, and specifications routinely mix V and kV within a single document.
Battery and electronics design
Cell voltages, logic thresholds and regulator margins are all quoted in volts and millivolts — pair with the Electric Charge Converter when sizing capacity.
Methodology & Editorial Standards
All conversions route through the volt, the SI unit of electric potential difference, defined as one joule per coulomb or equivalently one watt per ampere. The SI prefixes are exact powers of ten. The statvolt and abvolt from the CGS systems are included for legacy literature; the statvolt factor of 299.792458 derives from the exact defined speed of light. The dBu and dBV references are deliberately NOT unit rows, because a decibel is a logarithm of a ratio and cannot be represented as a multiplying factor; they appear as a derived card instead, and are undefined at zero volts. The 0 dBu reference of 0.7745966692414834 V is derived as the square root of one milliwatt into 600 ohms rather than typed from a source. RMS to peak conversion assumes a sinusoidal waveform and does not hold for square, triangular or distorted signals. All conversion factors are exact by definition under the International System of Units, or exact by international agreement where the unit is defined by treaty. Values are held at full IEEE-754 double precision internally and rounded only for display, so chained conversions do not accumulate drift.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Voltage Converter — 8 Expert FAQs
8 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
What is 0 dBu in volts?
0.7745966692 V RMS. The figure is the square root of one milliwatt dissipated into 600 ohms, which was the standard termination impedance of telephone and broadcast lines. The impedance convention disappeared decades ago but the reference voltage remained, which is why professional audio uses such an apparently arbitrary number.
What is the difference between dBu and dBV?
Only the reference. dBu is referenced to 0.7746 V and dBV to exactly 1 V, so the same voltage reads 2.2185 dB higher on the dBu scale. Professional equipment is specified at +4 dBu and consumer equipment at −10 dBV; the real difference between those two operating levels is 11.78 dB, not the 14 dB you get by naively subtracting the numbers.
Why is mains 230 V but peaks at 325 V?
Because 230 V is the RMS value, the DC-equivalent heating value of the waveform, while the sine wave actually swings to √2 times that at its peak, about 325 V, and 650 V peak to peak. Insulation, rectifier diodes and smoothing capacitors must all be rated for the peak, not the nominal figure.
Is a kilovolt exactly 1,000 volts?
Yes. All SI prefixes are exact powers of ten by definition, so there is no measurement uncertainty in any of the prefix conversions on this page. This is unlike the imperial conversions elsewhere in this suite, where exactness comes from international agreement on a specific decimal value.
Can voltage be negative?
Yes, and unlike most quantities in this converter suite it legitimately can be. Voltage is a potential difference between two points, so the sign simply records which point you took as reference. Split-rail supplies genuinely provide −15 V relative to ground. The decibel card is the exception, since it uses magnitude and is undefined at zero.
What is a statvolt?
The unit of potential in the electrostatic CGS system, equal to about 299.792458 volts. The number is exactly one hundred-millionth of the defined speed of light in metres per second, because the CGS electrostatic units are built around it. You will meet it in older physics texts and essentially nowhere in modern engineering.
Does higher voltage mean more danger?
Not by itself. Injury is caused by current through the body, which depends on the voltage, on skin and contact resistance and on the path the current takes. A static discharge of ten thousand volts is usually harmless because almost no charge is behind it, while a low-voltage battery capable of hundreds of amps can cause severe burns. Never treat a voltage figure as a safety assessment.
How do I convert volts to watts?
You cannot directly, because they measure different things. Power is voltage multiplied by current, so you need either the current or the resistance. With resistance, P = V²/R. This converter shows that cross-check on the Ohm's law card, but calculating circuit power properly belongs to a dedicated calculator rather than a unit tool.