Enter your planned value, earned value and actual cost and get your schedule and cost variance, SPI, CPI, forecast final cost and to-complete index, with a plain English verdict on each. No email needed.
Earned value management (EVM) is a project controls method that compares the value of work actually completed (EV) against what was planned to be completed (PV) and what it actually cost (AC), so schedule and cost performance can be measured objectively instead of by gut feel.
The three inputs are also known by their original PMI names: PV = Budgeted Cost of Work Scheduled (BCWS), EV = Budgeted Cost of Work Performed (BCWP), AC = Actual Cost of Work Performed (ACWP).Enter figures in any currency, in any consistent unit (pounds, thousands, whatever your project reports in). The forecast final cost (EAC) and to-complete index (TCPI) need your total approved budget (BAC) as well; leave it blank if you only want SV, CV, SPI and CPI.
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SPI (schedule performance index) and CPI (cost performance index) both work the same way: 1.0 means exactly on plan, above 1.0 means ahead or under budget, below 1.0 means behind or over budget. SV and CV work in your project's currency: positive is good, negative means a shortfall against the plan. EAC is your calculator's honest forecast of what the project will actually cost if current cost performance continues. TCPI is the cost efficiency you now need on every remaining pound to still hit your original budget, which is the number that tells you whether that budget is still realistic.
| Input | Value |
|---|---|
| PV (planned value) | £50,000 |
| EV (earned value) | £45,000 |
| AC (actual cost) | £50,000 |
| BAC (total budget) | £100,000 |
That gives SV = −£5,000, CV = −£5,000, SPI = 0.90, CPI = 0.90, EAC = £111,111 and TCPI = 1.10. In plain English: the project is both behind schedule and over budget, has already spent £11,111 more than its budget will support if nothing changes, and now needs 10% better cost efficiency on every remaining pound just to land on the original £100,000. Try these figures in the calculator above to see the full verdict text.
Knowing your CPI and SPI is only useful if the underlying records are complete. A calculator is only as accurate as the PV, EV and AC you feed it, and on most projects those numbers are reconstructed from memory at month end rather than tracked as the work happens.
Gather's AI QS keeps the site record complete and NEC aligned, so the variance you report is backed by evidence you can defend, not a spreadsheet nobody trusts.
See how Gather keeps your records claim ready A 30 minute call. No commitment. We will use your own project as the example.FAQ
SPI (schedule performance index) measures whether you are ahead or behind schedule in cost terms, using EV divided by PV. CPI (cost performance index) measures whether you are under or over budget, using EV divided by AC. A project can be behind schedule but under budget, or on schedule but over budget; the two indices are independent and both matter.
They are the original PMI terms for the same three earned value inputs now usually called PV, EV and AC: BCWS (Budgeted Cost of Work Scheduled) is PV, BCWP (Budgeted Cost of Work Performed) is EV, and ACWP (Actual Cost of Work Performed) is AC. UK construction reports increasingly use PV/EV/AC, but both sets of terms describe identical figures.
The most common method is EAC = BAC ÷ CPI, which assumes the cost performance seen so far continues for the rest of the project. BAC is your total original budget. This is the method this calculator uses; other EAC formulas exist for projects where future cost performance is expected to differ from past performance.
TCPI (to-complete performance index) above 1 means you need better cost efficiency than you have achieved so far on every remaining pound of budget to hit your original BAC. The higher above 1, the less realistic that original budget is becoming; a TCPI much higher than your current CPI is usually a signal the budget needs re-baselining rather than chased.
Yes. Earned value is contract-neutral, it measures physical progress against cost regardless of the form of contract. On NEC4 projects the PV baseline aligns naturally to the Accepted Programme and AC to Defined Cost, which is why EVM sits comfortably alongside NEC4 compensation event and payment mechanisms.
Gather turns the daily site record into evidence your CPI and SPI can actually stand behind.
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