Transformer Sizing Calculator
Static · formula-only · worked example computed when this page was built · no live data
The Transformer Sizing Calculator picks the standard kVA rating for a load with spare capacity and reports the resulting loading. Example: for a 100 kVA load on a 13.8 kV / 400 V 3-phase supply with 25% spare, Rated size = 150 kVA, Required capacity = 125 kVA, Loading = 66.7 % (per PEC 2017 Art. 4.50 | IEC 60076-1:2011).
How it works
Computed from your inputs per PEC 2017 Art. 4.50 | IEC 60076-1:2011. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
Worked example (Electrical & Power)
Inputs: a 100 kVA load on a 13.8 kV / 400 V 3-phase supply with 25% spare.
| Result | Value |
|---|---|
| Rated size | 150 kVA |
| Required capacity | 125 kVA |
| Loading | 66.7 % |
Computed by WorkHive's calculation engine when this page was built; standard: PEC 2017 Art. 4.50 | IEC 60076-1:2011.
How to use this calculator
- Read the worked example. It uses a 100 kVA load on a 13.8 kV / 400 V 3-phase supply with 25% spare and shows every number in the method.
- Follow the formula with your own figures: it returns Rated size, Required, Loading, computed per PEC 2017 Art. 4.50 | IEC 60076-1:2011.
- To compute interactively, open the Transformer Sizing Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
FAQ
What is a transformer sizing calculator kVA?
The Transformer Sizing Calculator is a free online tool that picks the standard kVA rating for a load with spare capacity and reports the resulting loading. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following PEC 2017 Art. 4.50 | IEC 60076-1:2011. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive is free: this worked example is open to everyone, and the interactive calculator runs inside the free Engineering Design suite after a free sign-up (your work is saved to your account). WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Transformer Sizing Calculator in WorkHive. Free, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.