1. What is CPI and SPI?

CPI (Cost Performance Index) and SPI (Schedule Performance Index) are key performance indicators used in project management to measure cost efficiency and schedule efficiency respectively. They help project managers assess project performance and make informed decisions.

2. How Do the Formulas Work?

The calculator uses the following formulas:

Where:

• \( EV \) — Earned Value (currency)
• \( AC \) — Actual Cost (currency)
• \( PV \) — Planned Value (currency)

Explanation:

• CPI > 1 indicates under budget (cost efficiency)
• CPI < 1 indicates over budget (cost inefficiency)
• SPI > 1 indicates ahead of schedule
• SPI < 1 indicates behind schedule

3. Importance of CPI and SPI Calculation

Details: These indices are crucial for project performance measurement, helping identify variances from the project plan early, enabling corrective actions, and supporting effective project control and decision-making.

4. Using the Calculator

Tips: Enter Earned Value (EV), Actual Cost (AC), and Planned Value (PV) in currency units. All values must be positive numbers with AC and PV greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What do CPI and SPI values indicate?
A: CPI measures cost efficiency (value for money spent), while SPI measures schedule efficiency (work completed vs planned).

Q2: What are ideal CPI and SPI values?
A: Values equal to 1 indicate project is on budget and on schedule. Values greater than 1 indicate better than planned performance.

Q3: How often should CPI and SPI be calculated?
A: Typically calculated during regular project status meetings, often weekly or monthly depending on project duration and complexity.

Q4: Can CPI or SPI be negative?
A: No, since all input values (EV, AC, PV) should be positive, the indices will always be positive numbers.

Q5: What actions should be taken if CPI or SPI is below 1?
A: Investigate root causes, implement corrective measures, reallocate resources, or revise project plans as necessary.