Transformer Sizing Calculator — kVA Rating

Disclaimer: For reference and estimation purposes only. Results are indicative. Verify all designs with qualified engineers before implementation. Dr Darla accepts no responsibility for decisions made based on these estimates.

Load details

Enter each load group connected to the transformer.

Total connected kVA 0.00 kVA

Transformer parameters

Diversity / demand factor (%) iNot all loads run simultaneously. Diversity factor accounts for this. Residential: 60–75%, Industrial: 80–90%, Critical: 100%. Residential: 70%, Industrial: 85%

Future load growth (%) iExtra capacity for future load additions. Typical: 20–30%. Large industrial: 25–50%.

Target loading (%) iRecommended operating loading of transformer. Run at 70–80% for efficiency and longevity. Never exceed 100%. Optimal: 70–80%

Primary voltage (V)

Secondary voltage (V)

Application type

Transformer recommendation

— kVA

Required capacity

— kVA

Standard size to select

— %

Loading at standard size

— A

Primary full-load current

Full calculation breakdown

Tool by Dr Darla — Power Electronics & Energy Systems Expert · View all calculators