Example Data Table
| Scenario | PV | EV | AC | BAC | CV | SV | CPI | SPI |
|---|---|---|---|---|---|---|---|---|
| Baseline month | 120,000 | 110,000 | 125,000 | 250,000 | -15,000 | -10,000 | 0.880 | 0.917 |
| Improved control | 120,000 | 118,000 | 121,000 | 250,000 | -3,000 | -2,000 | 0.975 | 0.983 |
| Ahead of plan | 120,000 | 130,000 | 129,000 | 250,000 | 1,000 | 10,000 | 1.008 | 1.083 |
These numbers are illustrative. Replace with your real project values.
Formula Used
- Cost Variance (CV) = EV − AC
- Schedule Variance (SV) = EV − PV
- Cost Performance Index (CPI) = EV ÷ AC
- Schedule Performance Index (SPI) = EV ÷ PV
- Estimate at Completion (EAC) = BAC ÷ CPI
- Variance at Completion (VAC) = BAC − EAC
- Time Variance = Actual Days − Planned Days
How to Use This Calculator
- Collect PV, EV, and AC for the same reporting cut-off.
- Enter BAC to forecast EAC and VAC.
- Optionally enter planned and actual duration for time variance.
- Click Submit to view results above the form.
- Use CPI and SPI to guide corrective actions.
- Download CSV or PDF to share with stakeholders.
Tip: Keep units consistent. If your currency is USD, use USD everywhere.
Performance Baseline and Reporting Cadence
Variance analysis works best when PV, EV, and AC are captured on the same cut‑off date. Weekly reporting is common for short projects, while biweekly or monthly cycles fit longer programs. A stable cadence reduces noise, supports trend lines, and makes CPI and SPI comparisons meaningful across periods. Record the reporting window, currency, and percent complete rule so that EV is calculated consistently across teams and vendors.
Cost Variance Interpreting Typical Ranges
CV highlights whether delivered work is costing more or less than planned. Many teams treat ±2% as a normal band, then escalate beyond ±5% to management review. Pair CV with CPI: a CPI of 0.90 implies you are getting 0.90 of value per currency unit spent. Track CPI by phase to see whether efficiency improves after ramp‑up or deteriorates in testing.
Schedule Variance and Delivery Risk
SV indicates whether earned value is keeping pace with planned value. A negative SV suggests slippage, even if the calendar shows progress. For example, SPI 0.95 can imply a 5% productivity gap. Track SV with critical path activities to confirm whether the gap threatens the end date.
Forecasting EAC and Managing Contingency
EAC projects final cost if current efficiency continues. When CPI is below 1.00, EAC rises above BAC, consuming contingency and reserves. Use VAC to quantify remaining budget buffer. If VAC turns negative early, prioritize scope control, procurement renegotiation, or productivity actions. A common check is EAC minus BAC as an overrun estimate; compare it to management reserve to decide whether change control is required.
Root Cause Patterns Found in Variance Data
Recurring drivers include underestimated effort, late design changes, rework, vendor delays, and unplanned overtime. Segment variance by work package to avoid averaging effects. If one package shows CPI 0.80 while others are near 1.00, focus corrective measures where they will move the total.
Executive Communication and Action Triggers
Stakeholder updates should translate metrics into decisions. Report current CV, SV, CPI, and SPI, then state the recommended action, owner, and due date. Common triggers are SPI < 0.95 for two cycles, CPI < 0.95, or VAC < 0, prompting a recovery plan and revised forecast.
FAQs
1) What inputs do I need for reliable variance results?
Use PV, EV, and AC from the same reporting cut-off date. Add BAC for forecasting. Keep currency and earned-value rules consistent across work packages.
2) What does a negative cost variance mean?
Negative CV means actual costs exceed earned value for completed work. It signals overspending relative to progress, and typically warrants reviewing productivity, scope changes, and procurement rates.
3) Can schedule variance be negative even if tasks look on track?
Yes. SV compares earned value to planned value, not task counts. If high-value deliverables are late, SV can be negative even when many lower-value tasks are complete.
4) How should I interpret CPI and SPI together?
CPI reflects cost efficiency and SPI reflects schedule efficiency. CPI below 1.00 and SPI below 1.00 indicate you are both over budget and behind plan, requiring coordinated recovery actions.
5) Why does EAC use BAC divided by CPI?
This approach assumes the current cost efficiency continues. If CPI is 0.90, dividing BAC by 0.90 forecasts a higher completion cost. Use it as a baseline forecast, then refine with known changes.
6) When should I escalate variance to leadership?
Common triggers include CPI or SPI below 0.95 for two reporting cycles, a negative VAC, or rapid month-to-month deterioration. Escalate with a clear cause, options, and an owner for next steps.