CT / PT Ratio & Scaling Calculator

Determine the transformation ratio of your current or voltage transformer, scale secondary meter readings to primary values, and check burden impedance.

CT / PT Ratio Calculator

Instrument Transformer Type

Primary Current (A)

Secondary Current (A)

Primary Voltage (V)

Secondary Voltage (V)

Burden (VA)

Measured Secondary Value (A or V, for scaling)

Results

Transformation Ratio200/5

Ratio:40 : 1

Actual Primary Value (from measured):140 A

Burden Impedance (Ω):0.60 Ω

CT Class Recommendation:Class 0.5 (metering)

FormulaRatio = Ip / Is | Primary = Measured × Ratio

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