Transformer Calculators: Free Tools for Sizing & Voltage Ratio
Size transformers accurately for any application with our free online transformer calculators. Whether you need a step-down unit for residential service, a step-up transformer for industrial distribution, or an isolation transformer for sensitive equipment, these tools calculate required kVA, voltage ratios, and efficiency instantly. Enter your load current, primary and secondary voltages, and power factor to determine the minimum transformer rating that handles your demand safely. Each calculator includes turns ratio, impedance percentage, and voltage regulation results to ensure proper selection. Electricians and engineers use these tools to avoid undersizing that causes overheating or oversizing that wastes capital. From small control transformers to large power distribution units, get NEC-aligned sizing recommendations with no signup required. Access from desktop or mobile and complete transformer specifications in minutes instead of hours.
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Secondary Voltage Calculator
Calculate transformer secondary voltage using primary voltage and turns ratio. Simple tool with formula, examples, and data tables for fast results.
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Transformer Voltage Calculator
Easily calculate transformer output voltage using turns ratio or input voltage. Includes formulas, conversion tables, worked examples, and FAQs for quick reference.
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Full Load Current Turns Ratio calculator for Transformer
Compute transformer full-load current for single/three-phase and find turns ratio a = Np/Ns = Vp/Vs = Is/Ip. Includes examples and quick reference tables.
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Calculate kVA Size for Single & Three Phase Transformers
Easily calculate transformer kVA size for single-phase and three-phase loads using kW, power factor, voltage, and current with formulas and tables.
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Transformer kVA Calculator Based on Load
Easily calculate transformer kVA size from load in kW or HP, voltage, and power factor. Supports single-phase and three-phase calculations.
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No-load voltage calculator
Calculate the no-load (open circuit) voltage of generators, transformers, or other sources using EMF equations, winding data, and test parameters.
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Tap voltage calculator
Calculate transformer tap voltage to match supply and load requirements. Ideal for power engineers and electricians to ensure correct voltage delivery.
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step down voltage calculator
Easily calculate output voltage when stepping down AC or DC using transformers or voltage dividers. Ideal for electronics, power supply design, and safety.