Schedule Variance Calculator
This tool calculates the Schedule Variance (SV) for a project task or work package. Schedule Variance measures whether your project is ahead or behind schedule, based on the difference between the value of work actually completed (Earned Value) and the value of work planned to be completed (Planned Value) by a specific point in time.
Enter the Earned Value (EV) and the Planned Value (PV) at a specific status date. Ensure both values are in the same currency or unit of measure.
Enter Project Values at Status Date
Understanding Schedule Variance (SV)
What is Schedule Variance (SV)?
Schedule Variance (SV) is a key Earned Value Management (EVM) metric used in project management. It indicates how far ahead or behind schedule a project or task is, based on cost or labor hours. It measures the difference between the value of the work you have actually completed versus the value of the work you planned to complete by a specific point in time (the status date).
Schedule Variance Formula
The formula for Schedule Variance is simple:
SV = Earned Value (EV) - Planned Value (PV)
- Earned Value (EV): The budgeted cost of the work *performed* up to the status date. It's the value you have "earned" through completing work.
- Planned Value (PV): The budgeted cost of the work *scheduled* to be performed up to the status date. It's what you "planned" to have spent/earned by this point.
Interpreting Schedule Variance
- SV > 0 (Positive): The project or task is **ahead of schedule**. The value of work completed is more than planned.
- SV < 0 (Negative): The project or task is **behind schedule**. The value of work completed is less than planned.
- SV = 0 (Zero): The project or task is **exactly on schedule**. The value of work completed matches the plan.
While SV tells you *if* you are ahead or behind, it doesn't directly tell you *how much* time you are ahead or behind. For that, you often use the Schedule Performance Index (SPI = EV / PV).
Schedule Variance Examples
Here are some examples demonstrating the calculation and interpretation of Schedule Variance:
Example 1: Ahead of Schedule
Scenario: A software development task was planned to have $5,000 worth of work completed by the end of week 2. At the end of week 2, the actual completed work is valued at $6,000.
1. Known Values: Earned Value (EV) = $6,000, Planned Value (PV) = $5,000.
2. Formula: SV = EV - PV
3. Calculation: SV = $6,000 - $5,000
4. Result: SV = $1,000
Conclusion: The task is $1,000 ahead of schedule.
Example 2: Behind Schedule
Scenario: By the project's first month review, the plan was to have completed work valued at $15,000. The work actually completed is valued at $12,000.
1. Known Values: Earned Value (EV) = $12,000, Planned Value (PV) = $15,000.
2. Formula: SV = EV - PV
3. Calculation: SV = $12,000 - $15,000
4. Result: SV = -$3,000
Conclusion: The project is $3,000 behind schedule.
Example 3: On Schedule
Scenario: A marketing campaign milestone was scheduled to achieve $2,500 in completed value by the checkpoint. The work completed is assessed to have a value of $2,500.
1. Known Values: Earned Value (EV) = $2,500, Planned Value (PV) = $2,500.
2. Formula: SV = EV - PV
3. Calculation: SV = $2,500 - $2,500
4. Result: SV = $0
Conclusion: The milestone is exactly on schedule.
Example 4: Zero Work Planned, Zero Work Done
Scenario: At the very beginning of a project, the status date is before any work is scheduled or completed.
1. Known Values: Earned Value (EV) = $0, Planned Value (PV) = $0.
2. Formula: SV = EV - PV
3. Calculation: SV = $0 - $0
4. Result: SV = $0
Conclusion: The project is on schedule (at the very start).
Example 5: Work Done, But None Planned Yet
Scenario: An eager team gets ahead and completes $1,000 worth of work before the project plan even shows any work scheduled by the status date.
1. Known Values: Earned Value (EV) = $1,000, Planned Value (PV) = $0.
2. Formula: SV = EV - PV
3. Calculation: SV = $1,000 - $0
4. Result: SV = $1,000
Conclusion: The project is $1,000 ahead of schedule.
Example 6: Planned Work, But None Done Yet
Scenario: By the status date, $3,000 worth of work was planned, but due to delays, no work has actually been completed yet.
1. Known Values: Earned Value (EV) = $0, Planned Value (PV) = $3,000.
2. Formula: SV = EV - PV
3. Calculation: SV = $0 - $3,000
4. Result: SV = -$3,000
Conclusion: The project is $3,000 behind schedule.
Example 7: Mid-Project Checkpoint (Large Project)
Scenario: At the halfway point of a large construction project, the total planned value up to this point is $1,500,000. The earned value reported is $1,450,000.
1. Known Values: Earned Value (EV) = $1,450,000, Planned Value (PV) = $1,500,000.
2. Formula: SV = EV - PV
3. Calculation: SV = $1,450,000 - $1,500,000
4. Result: SV = -$50,000
Conclusion: The project is $50,000 behind schedule at this checkpoint.
Example 8: Small Task Analysis
Scenario: A small research task had a planned value of $500 by Wednesday. By Wednesday, $650 worth of the research is completed.
1. Known Values: Earned Value (EV) = $650, Planned Value (PV) = $500.
2. Formula: SV = EV - PV
3. Calculation: SV = $650 - $500
4. Result: SV = $150
Conclusion: The task is $150 ahead of schedule.
Example 9: End of Project (Planned vs. Actual Completion)
Scenario: At the *scheduled* project completion date, the total Planned Value (Budget At Completion) is $100,000. However, only $95,000 worth of work is actually completed.
1. Known Values: Earned Value (EV) = $95,000, Planned Value (PV) = $100,000.
2. Formula: SV = EV - PV
3. Calculation: SV = $95,000 - $100,000
4. Result: SV = -$5,000
Conclusion: The project is $5,000 behind its planned schedule completion value.
Example 10: End of Project (Fully Completed)
Scenario: At the *actual* project completion date, all work is finished. The total Planned Value (Budget At Completion) was $100,000. The total Earned Value will equal the total planned value once the project is 100% complete.
1. Known Values: Earned Value (EV) = $100,000, Planned Value (PV) = $100,000 (assuming the status date is the point where 100% completion was planned).
2. Formula: SV = EV - PV
3. Calculation: SV = $100,000 - $100,000
4. Result: SV = $0
Conclusion: At the point where 100% was planned to be complete, the project was exactly on schedule (in terms of planned value vs earned value). Note: This doesn't account for *when* it finished, only the value completed *by* the planned date vs *value planned* by that date.
About EVM Metrics
Schedule Variance is one of several key metrics in Earned Value Management (EVM). Others include Cost Variance (CV = EV - AC) and performance indices like SPI (EV/PV) and CPI (EV/AC). Together, these metrics provide powerful insights into project performance regarding both schedule and budget.
Using Consistent Units
It is crucial that Earned Value (EV) and Planned Value (PV) are measured in the same units. Typically, this is a currency (e.g., USD, EUR) but it could theoretically be labor hours or other consistent measures of value.
Ensure EV and PV are in the same currency (e.g., dollars, pounds, euros) or units (e.g., labor hours).
Frequently Asked Questions about Schedule Variance
1. What does a positive Schedule Variance (SV > 0) mean?
A positive SV means that the project or task is ahead of schedule relative to the plan at the specified status date. You have completed more work (in terms of value) than was planned by that time.
2. What does a negative Schedule Variance (SV < 0) mean?
A negative SV means that the project or task is behind schedule relative to the plan at the specified status date. You have completed less work (in terms of value) than was planned by that time.
3. What does a Schedule Variance of zero (SV = 0) mean?
An SV of zero means the project or task is exactly on schedule in terms of earned value versus planned value. The value of work completed matches the value of work planned by the status date.
4. Is a positive SV always good?
Generally, yes, as it indicates being ahead of schedule. However, it's worth investigating *why*. It could be due to efficient work, but it could also be due to scope creep (doing more work than planned), which might impact budget or quality later.
5. Is a negative SV always bad?
A negative SV is a warning sign that the project is running behind schedule. This often requires corrective action to get back on track, which might involve adding resources, working overtime, or replanning.
6. What are the required inputs for this calculator?
You need to provide the Earned Value (EV) and the Planned Value (PV) for the project or task at a specific point in time (the status date).
7. How do I get the Earned Value (EV) and Planned Value (PV)?
EV and PV are calculated as part of the Earned Value Management process. PV comes directly from your project schedule and budget. EV is calculated by determining the percentage of completion for scheduled tasks and multiplying it by the budgeted cost for those tasks.
8. What units should I use for EV and PV?
You must use the same units for both EV and PV. This is almost always the project's currency (e.g., dollars, euros). Using different units will give a meaningless result.
9. How does Schedule Variance relate to Schedule Performance Index (SPI)?
SV is an absolute measure (a dollar or currency amount), while SPI (calculated as EV / PV) is a relative measure (a ratio). SPI = 1 means on schedule, SPI > 1 means ahead, and SPI < 1 means behind. SV tells you *by how much value* you are off schedule; SPI tells you *how efficiently* you are progressing against the schedule.
10. Can SV be used for individual tasks or only the whole project?
SV can be calculated and analyzed at various levels within a project's Work Breakdown Structure (WBS), from individual work packages to major project phases and the overall project.
