Estimate to Complete (ETC)
The Estimate to Complete, or ETC, answers a very practical question: "From this point onward, how much more money will we need to finish the remaining work?" Notice that ETC is about the future only — it deliberately ignores money already spent and focuses on the road still ahead.
To calculate it, you need two terms. "Estimate at Completion" (EAC) is your forecast of what the entire project will cost in total by the time it's finished, including money already spent and money still to be spent. "Actual Cost" (AC) is the money you have spent so far. ETC is simply EAC minus AC — the total forecast minus what you've already paid, which leaves the cost of what remains.
A project manager uses ETC to plan cash flow and to tell sponsors how much more funding is required to reach the finish line. A large ETC means a lot of expensive work still lies ahead; a small ETC means you're nearly done spending. It's especially useful for approving budgets in stages, because it isolates the cost of the future rather than mixing it with the past.
Think of it like a long taxi ride where the meter already reads ₹300, and you estimate the full trip will cost ₹500. The ₹200 still to be added on the meter before you arrive is your Estimate to Complete — it's only the money the road ahead will cost, not what you've already run up.
Say you forecast the whole project will end up costing ₹5,00,000 in total — that's your Estimate at Completion (EAC = ₹5,00,000). So far you've already spent ₹3,00,000 — that's your Actual Cost (AC = ₹3,00,000). ETC = EAC − AC = 5,00,000 − 3,00,000 = ₹2,00,000. This tells you that you'll need about ₹2,00,000 more to complete the remaining work.
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