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Schedule Performance Index Calculator

Calculate SPI from earned value and planned value and see whether earned progress is ahead of or behind plan.

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SPI compares earned progress with planned progress.

Budgeted value of work completed.
Budgeted value planned by the status date.
Used for schedule variance display.
Methodology note. Formulas are based on established Earned Value Management terminology. Core references include Project Management Institute (PMI) educational resources and U.S. Department of Energy EVM guidance. Last reviewed: August 14, 2026. Read methodology · View sources

SPI formula

SPI = EV ÷ PV

An SPI of 1.00 means earned progress equals planned progress at the status date. Below 1.00 is behind plan; above 1.00 is ahead in earned-value terms.

SPI is not a duration ratio

Traditional SPI is expressed in budgeted value, so it should not be read as a direct promise that a project will finish a specific percentage early or late. For forecasting cost, some EAC scenarios combine CPI and SPI when both cost and schedule performance are assumed to influence the remaining work.

See the Schedule Variance Calculator for the currency-value difference between EV and PV.