Electrical Power Converter

What the electrical power converter solves

The calculator converts between real power, apparent power, current, voltage, resistance, and horsepower when the required context is available. For DC and simple resistive checks, watts, volts, amps, and ohms can often be rearranged from two compatible values. For AC, power factor and phase type matter because volt-amps and watts are not always the same thing.

Use the preset chips for common old-page intents such as amps to watts, watts to amps, amps to kW, kW to amps, kVA to kW, kW to kVA, VA to kW, kVA to watts, horsepower to amps, and amps to horsepower. Each preset loads an example without creating another indexable URL.

The master also keeps the more specific watts to VA calculator and kVA to horsepower calculator workflows available as hash-addressable presets. Those workflows need extra context: watts-to-VA planning should keep apparent power, reactive power, and power-factor sensitivity visible, while kVA-to-horsepower planning should keep the power-factor and efficiency assumptions attached to the horsepower estimate.

DC, single-phase AC, and three-phase AC formulas

DC and simple resistive calculations use the direct relationship P = V x I. When resistance is involved, Ohm's law adds V = I x R, which lets the calculator solve for ohms, volts, amps, or watts from compatible pairs.

Single-phase AC uses apparent power S = V x I and real power P = S x PF. Balanced three-phase AC uses S = sqrt(3) x V x I when the voltage is line-to-line, or S = 3 x V x I when the entered voltage is line-to-neutral. Real power is still apparent power multiplied by power factor.

Amps to watts, watts to amps, and voltage-dependent conversions

Amps cannot be converted to watts without voltage, and AC conversions also need power factor. For example, 15 amps at 120 volts and PF 1 is 1,800 watts, while the same current at 240 volts is 3,600 watts. The converter keeps voltage visible so the result is not a misleading one-number shortcut.

The reverse problem is similar. To convert watts to amps, divide real power by the voltage term and, for AC, by power factor and the phase multiplier. This is why a kW to amps calculator, watts to amps calculator, and volts to amps calculator all need more context than their names suggest.

Using common voltage shortcuts without hiding assumptions

Competitor three phase power calculator pages often lead with common voltages such as 208 V, 400 V, 415 V, and 480 V because those values answer the first practical question: which line voltage belongs in the amps, kW, and kVA formula. This calculator now keeps that convenience while still showing the editable voltage field and the selected system type.

Use the DC shortcuts for battery banks, low-voltage controls, and resistive checks where watts equal volts times amps. Use the single-phase shortcuts for branch-circuit style estimates. Use the three-phase shortcuts when your voltage is line-to-line; if a drawing gives line-to-neutral voltage instead, switch the voltage-basis control before trusting the result.

The shortcut is only a starting point. Equipment nameplates, measured voltage, supply configuration, and local installation details can differ from a generic 120 V, 230 V, 240 V, 208 V, 400 V, 415 V, or 480 V preset, so the page keeps the actual voltage input in the main workflow rather than burying it behind a fixed table.

kW, VA, kVA, and power factor

Watts and kilowatts are real power. VA and kVA are apparent power. In AC systems, power factor links the two: kW = kVA x PF. A 50 kVA load at 0.8 PF is 40 kW, while the same 50 kVA at 1.0 PF is 50 kW.

This distinction preserves the old kVA to kW, kW to kVA, kVA to watts, watts to kVA, VA to kW, kW to VA, kVA to VA, and VA to kVA search intents without maintaining separate pages that repeat the same explanation. The result table shows both real and apparent power so the relationship stays visible.

Watts to VA planning for UPS, generator, and inverter loads

The watts-to-VA preset starts from a practical planning example: 500 W at power factor 0.8 becomes 625 VA and 0.625 kVA. That mirrors the situation where a load list is written in watts but the UPS, inverter, transformer, generator, or source capacity is rated in VA or kVA.

The calculator does not stop at the headline conversion. It also shows the ideal reactive-power value, the apparent-power multiplier, and sensitivity rows across common power-factor assumptions. This keeps the old UPS sizing watts to VA, generator watts to VA calculator, and convert watts to VA intent intact after consolidation.

Use the sensitivity table when the power factor is uncertain. At PF 1.0, watts and VA are equal; at PF 0.8, apparent power is 1.25 times the watt load; at lower power factors the capacity gap grows. The capacity checkpoints then compare the required VA against common apparent-power bands so tight margins are visible before a device is selected.

Horsepower, amps, and motor assumptions

Horsepower conversions require an efficiency assumption because motor horsepower usually describes mechanical output, not electrical input. The calculator converts horsepower to electrical input power by dividing by motor efficiency, then applies voltage, phase, and power factor to estimate current or kVA.

For example, a 10 hp motor is about 7.46 kW of mechanical output. At 90% efficiency the electrical input is higher, and at PF 0.85 the kVA is higher again. This is why horsepower to amps, amps to horsepower, horsepower to kVA, and kVA to hp conversions should always show power factor and efficiency.

kVA to horsepower conversion intent

The kVA to horsepower preset handles the reverse planning question: given an apparent-power allowance, what approximate mechanical horsepower does it support after power factor and motor efficiency are applied? A 10 kVA value at PF 0.8 and 90% efficiency corresponds to about 8 kW of real electrical power before the horsepower-equivalent output is displayed.

This is not a nameplate motor selection rule. It is a translation layer for early planning notes where one document speaks in kVA and another speaks in horsepower. The result table keeps kW, watts, kVA, power factor, efficiency, and horsepower together so the kVA to horsepower calculator intent is not reduced to a bare conversion factor.

Worked example: three-phase amps to kW and kVA

Suppose a balanced three-phase motor draws 32 amps from a 400 V line-to-line supply at PF 0.85. Apparent power is sqrt(3) x 400 x 32, or about 22.17 kVA. Real power is 22.17 x 0.85, or about 18.85 kW.

If you reverse the workflow with the kW to amps preset, the same voltage and power factor produce essentially the same current. That reversibility is a useful check before copying a result into equipment notes, load schedules, or early generator sizing calculations.

When this calculator is not enough

This page is an electrical arithmetic and unit-conversion tool. It does not size conductors, breakers, fuses, transformers, generators, motor starters, inverters, UPS systems, or protective devices. It also does not model unbalanced three-phase loads, harmonic distortion, waveform shape, inrush current, temperature derating, voltage drop under load, local electrical-code rules, or manufacturer-specific equipment limits.

For mains circuits, motors, generators, batteries, solar equipment, or safety-critical designs, treat the result as a transparent planning check and verify it against product data, applicable codes, and a qualified professional.