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Independent Estimate at Completion

Independent Estimate at Completion (IEAC)

EVM Terms Reviewed by forProject Technology - updated Sep 2026
Quick definition: An Independent Estimate at Completion (IEAC) is a cost forecast calculated using a standard formula based on past performance, used to sanity-check the manager's own Estimate at Completion.

Rather than relying on a manager's judgment-based EAC, an IEAC is derived mathematically from historical cost or schedule efficiency — a commonly used version is IEAC = BAC/CPI, where CPI = BCWP/ACWP. Since different formulas assume different future efficiency scenarios, several IEACs are often calculated to give a range of optimistic-to-pessimistic outcomes.

Why it matters

Comparing one or more IEACs against the manager's EAC helps a Program Manager judge whether that EAC looks reasonable, or whether it deserves closer scrutiny. It doesn't necessarily mean the manager's estimate is wrong, but a large gap is usually a signal to dig deeper.

Also known as
IEAC
Used in
IEAC = BAC / CPI (where CPI = BCWP / ACWP)

FAQ

Does a different IEAC mean the manager's EAC is wrong?
Not necessarily — a gap between the two just suggests further analysis or discussion may be warranted, since the manager's EAC may account for factors a formula-based estimate can't capture.
What does the IEAC = BAC/CPI formula assume?
It assumes the project will continue completing its remaining work at the same cost efficiency (CPI) it has shown so far.
Definition maintained by forProject Technology.
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