load to voltage calculator
Estimate the voltage required by a load using power, current, or resistance. Enter known values (W, A, Ω) to instantly compute voltage for DC or resistive AC systems.

calculate voltage from load
To calculate the voltage that a load should have, the amount of power that a load will have (watts) is used and divided by the amount of current a load will have (amps): V = P 1 I. Where resistance is known, and the current is unknown, use V = V = /(P R). This is an immediate result where the values are input in terms of units.
Formula & Table Summary:
- V = P / I (Voltage = Power ÷ Current)
- V = √(P × R) (Resistive loads)
- P = V × I ; I = P / V ; P = V² / R
Units: P in W, I in A, V in V, R in Ω. Use RMS/impedance for reactive AC.
resistance-to-voltage calculator
A Load to Voltage Calculator will use the power, current, or resistance of a load to calculate the required voltage. Apply V = P/I when the current is known, or V = 2 (P / R) in the resistive load. Perfect to power-supply sizing, lab checks, and homework-enter in base units, and up pops the answer. A Load To Voltage Calculator identifies the voltage that should be applied to a load on the basis ofthe power consumption of the load, the current it takes, or its resistance. This calculator is DC- and purely resistive-AC loads oriented; reactive AC systems cannot be calculated without RMS and impedance calculations. It is functional as an electrical design check, sizing power supplies, bench testing, and educational. The tool processes unit-sensitive entries (can convert mA to base units, etc), displays work-formulas, and provides an unambiguous output with possible rounded values. You simply put in two values that can be compatible and obtain the necessary voltage in volts (V) within no time.
watt-to-volt load calc
Power (W) | Current (A) | Resistance (Ω) | Calculation | Voltage (V) |
---|---|---|---|---|
48 | 2.0 | — | V = 48 / 2.0 | 24.0 |
20 | — | 10 | V = √(20 × 10) | 14.142 |
150 | 5.0 | — | V = 150 / 5.0 | 30.0 |
0.5 | 0.02 | — | V = 0.5 / 0.02 | 25.0 |
360 | 12.0 | — | V = 360 / 12.0 | 30.0 |
Frequently Asked Questions - load to voltage calculator:
How do I calculate voltage for a load?
Divide power (W) by current (A): V = P / I.
What if I know load resistance instead of current?
Use V = √(P × R) for resistive loads when power and resistance are known.
Which units should I use?
Use base units: watts (W), amperes (A), volts (V), ohms (Ω). Convert mW/mA/kW first.
Can I use this for AC loads?
Yes for purely resistive AC using RMS values; reactive AC needs impedance and phase considerations.
How to find current if I know voltage and power?
I = P / V.
Is P = V × I always true?
Yes — P = V × I is the core relation for instantaneous power in DC and resistive circuits.
How to combine multiple loads?
Sum individual powers for parallel loads, then use total power with total current to find system voltage.
Does temperature affect results?
Resistance can change with temperature; use operating-temperature resistance for best accuracy.
Can I enter milliamps or milliwatts?
Yes — convert to amps/watts first or use a unit-aware input that converts automatically.
What’s a quick example?
A 100 W load drawing 4 A requires V = 100 / 4 = 25 V.
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