Transformer loss calculator and efficiency curve

Engineering Tool

Transformer Loss Calculator

Estimate transformer efficiency, no-load loss, load loss, yearly kWh loss, and electricity cost. Compare two designs to see which option is cheaper to operate.

Real Load Curve

Loss x Load^2

Transformer and Load Data

kVA
%
h/day
USD / kWh

Option A - Baseline Transformer

W
W

Option B - Low-Loss Transformer

W
W

Please enter valid capacity, load, and loss values.

Efficiency results will appear here

Use transformer test report losses or manufacturer guaranteed loss values.

Option A Efficiency

at selected load

Annual Cost

Option A loss

Savings

B vs A / year

Efficiency Curve

Load loss changes with load squared; no-load loss is constant.

Option A Option B

Loss and Cost Breakdown

Metric Option A Option B

Engineering Notes

  • No-load loss is present whenever the transformer is energized, even with no load connected.
  • Load loss rises approximately with the square of load current: loss at 50% load is about 25% of rated load loss.
  • For 24/7 utility or industrial operation, a lower-loss transformer can recover a higher purchase price through reduced energy loss.
  • Final guarantees should be based on the transformer routine test report and the project standard, such as IEC 60076 or ANSI/IEEE C57.12.

How to Use Loss Values

What Numbers Should You Enter?

Use guaranteed no-load and load-loss values from a manufacturer datasheet, tender document, or routine test report. If you only know capacity and voltage, send the project data to XinHuan and we can recommend an appropriate loss level.

No-Load Loss P0

Core loss in watts. It depends on core material and is present whenever the transformer is energized.

Load Loss Pk

Copper/winding loss at rated current. Actual load loss is Pk multiplied by load ratio squared.

Average Load

Use expected average operating load, not only peak load. Energy cost depends heavily on this value.