Schedule Performance Index Calculator

Schedule Performance Index Calculator

This calculator expresses schedule health as a comparable ratio, useful for benchmarking across projects of different sizes.

Schedule Performance Index (SPI) = Earned Value(EV) / Planned Value(PV)

Example

$80,000 earned value against $100,000 planned value:

SPI = 80,000 / 100,000 = 0.80 (Behind Schedule)

Reading the Ratio

An SPI above 1.0 indicates the project is progressing faster than planned, while below 1.0 indicates it's falling behind - unlike Schedule Variance (a dollar amount), SPI's ratio format makes it directly comparable across projects with very different total budgets.

Using CPI and SPI Together

Reviewing SPI alongside CPI (Cost Performance Index) gives a fuller project health picture than either alone - a project can be ahead of schedule but over budget, or vice versa, and these two metrics together reveal exactly which type of problem (if any) is occurring.