Forecast what your project will actually cost. Enter your budget, earned value and actual cost, and get your Estimate at Completion, the estimate to complete, and how far over or under budget you're heading.
The Estimate at Completion (EAC) is the forecast total cost of a project given how it's performing so far. Where BAC is what you planned to spend, EAC is what you now expect to spend. The gap between them — the variance at completion (VAC) — is the early warning every budget owner wants.
This is the most widely used EAC formula. It assumes your current cost efficiency (CPI) continues for the rest of the work. From it: ETC = EAC − AC (the cost of the work still to come) and VAC = BAC − EAC (how far over or under you'll land).
BAC / CPI is a fine early warning, but it is an extrapolation, not an estimate — it assumes the rest of the job runs exactly like the job so far. The EAC I trust is the one where somebody has re-estimated the remaining work.
In practice I run both: the formula to detect drift, and a bottom-up estimate-to-complete, reduced against actuals each period, to forecast with. When the two diverge, that gap is the agenda for the month's review.
A $4.2M project (BAC) has earned $1.85M of work (EV) and spent $1.9M (AC). CPI = 1.85 / 1.9 = 0.97. So EAC = 4.2 / 0.97 = $4.33M, ETC = 4.33 − 1.9 = $2.43M still to spend, and VAC = 4.2 − 4.33 = −$130k — a forecast $130k overrun. A 3% cost slip today becomes a six-figure miss at completion, which is exactly why EAC is worth watching from early on.
When the overrun to date is a one-off, use EAC = AC + (BAC − EV) — the remaining work reverts to plan. When both cost and schedule pressure will persist, use EAC = AC + (BAC − EV) / (CPI × SPI) — the most pessimistic of the three, and the one to run when a client asks "what's the worst case?". This calculator runs all three — pick the formula above the inputs. The full earned value calculator shows the inputs behind them.
EAC (Estimate at Completion) is the forecast total cost based on performance to date. The common formula is EAC = BAC / CPI.
EAC = BAC / CPI, where CPI = EV / AC. A $4.2M budget at CPI 0.97 forecasts EAC ≈ $4.33M.
BAC / CPI (efficiency continues); AC + (BAC − EV) (remaining reverts to plan); AC + (BAC − EV) / (CPI × SPI) (cost and schedule persist). This tool runs all three — pick the formula that matches your assumption about the remaining work.
Aegis computes EAC from your live schedule every period and pairs it with a 1,500-run Monte-Carlo completion date — so your cost and time forecasts come from the same source of truth.
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