Sizes a new transformer — or an N-1 redundant group — from connected load, growth/safety margins, ambient + altitude derating (IEC 60076-1/2/11-aligned reference conditions), and standard ANSI/IEEE or IEC preferred kVA ratings. For analyzing losses/efficiency of an existing transformer, see the Generator & Transformer Analysis calculator instead. Fully free — no subscriber gate.
IEC 60076-1/2/11
Generated
For preliminary engineering use only — always verify results against project-specific standards and a qualified engineer's review before use in a real design.
With N total units, any (N−1) must be able to carry the full design load alone — N=2 (the common 1-for-1 redundant pair) sizes each unit for 100% of the load; N=1 means no redundancy. Ambient/altitude derating rates above the IEC reference points are commonly published engineering rules of thumb — always confirm against the manufacturer's thermal/altitude rating curve for a final selection.