Professional Electrical Engineering Tools

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Accurate, trustworthy, and easy-to-use electrical calculators and tools for engineers, electricians, students, and makers, together with professional services and in-depth practical guides.

Used by engineers & electricians worldwide

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Kilowatts to Amps Calculator

Convert kW to amps for DC, single-phase, and three-phase circuits. Enter power, voltage, and power factor to get amperes, with formula and chart.

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Amps to Kilowatts Calculator

Convert amps to kW for DC, single-phase, and three-phase circuits. Enter current, voltage, and power factor to get kilowatts, with formula and chart.

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kVA to Amps Calculator

Convert kVA to amps for single-phase and three-phase AC. Enter apparent power and voltage to get the current in amperes, with a transformer chart.

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Battery Capacity Calculator

Calculate battery capacity in watt hours, amp hours, and kWh. Enter voltage and Ah, Wh, or watts and runtime. Works for all battery types.

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Battery Size Calculator

Calculate what battery size you need for solar, inverter, UPS, RV, or home backup. Enter your load, runtime, and voltage, get results in Ah and Wh instantly.

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Wire Size Calculator

Wire size calculator for any load. Get the right AWG or mm² conductor or cable, sized for ampacity and voltage drop, per NEC, IEC/BS or AS/NZS.

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Power Conversion

29 calculators

Battery

24 calculators

Unit & Prefix Converters

4 calculators

Wire & Cable

2 calculators

Featured Tool

Battery Size Calculator

Find the battery capacity you need in amp-hours (Ah) and watt-hours (Wh) for solar, backup, inverter, UPS, or off-grid systems.

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Why Use OhmNexus?

We provide accurate, easy-to-use calculators for electrical engineering and practical electrical work. Whether you're sizing wire, checking voltage drop, or designing circuits, our tools help you get results quickly and correctly.

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