PMP exam formulas are easier to handle when you understand what each calculation tells you instead of trying to memorize a long list of equations. Once you know the formulas, the next step is applying them inside realistic scenarios, which is where a PMP exam simulator can help you practice recognizing the right calculation and interpreting the result under exam-style conditions.
PMI does not publish an official list of exactly 15 formulas that every candidate must memorize, and it does not guarantee a particular number or percentage of calculation questions on the current PMP exam. This guide therefore focuses on 15 practical project management calculations that are useful to understand during PMP exam preparation, especially earned value management, forecasting, estimating, and scheduling calculations.
The goal is not just to remember an equation. You should be able to recognize when it applies, calculate it correctly, and understand what the answer means for the project.
The 15 PMP Exam Formulas
- 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 using CPI: EAC = BAC ÷ CPI
- Estimate at Completion when future work follows the original plan: EAC = AC + (BAC − EV)
- Estimate at Completion using CPI and SPI: EAC = AC + (BAC − EV) ÷ (CPI × SPI)
- Estimate to Complete: ETC = EAC − AC
- Variance at Completion: VAC = BAC − EAC
- To-Complete Performance Index based on BAC: TCPI = (BAC − EV) ÷ (BAC − AC)
- To-Complete Performance Index based on EAC: TCPI = (BAC − EV) ÷ (EAC − AC)
- PERT Expected Duration: (O + 4M + P) ÷ 6
- PERT Standard Deviation: (P − O) ÷ 6
- PERT Variance: ((P − O) ÷ 6)2
- Total Float: LS − ES or LF − EF
PMP Cheat Sheet: Terms to Know Before Using the Formulas
Many PMP calculations use the same earned value management terms. Understanding these abbreviations will make the formulas much easier to remember.
- PV, Planned Value: The budgeted value of work that should have been completed by a particular point.
- EV, Earned Value: The budgeted value of work actually completed.
- AC, Actual Cost: The actual cost incurred for the work performed.
- BAC, Budget at Completion: The total approved budget for the project.
- EAC, Estimate at Completion: The current forecast of the project’s total cost at completion.
- ETC, Estimate to Complete: The expected cost required to complete the remaining work.
- O: Optimistic estimate.
- M: Most likely estimate.
- P: Pessimistic estimate.
- ES: Early Start.
- EF: Early Finish.
- LS: Late Start.
- LF: Late Finish.
For the earned value examples below, assume a project has the following values:
- BAC = $100,000
- PV = $50,000
- EV = $45,000
- AC = $50,000
1. Cost Variance: CV = EV − AC
Cost Variance tells you whether the value of the work completed is greater or less than what you actually spent to produce it.
Formula: CV = EV − AC
Using the example:
CV = $45,000 − $50,000 = −$5,000
The project has a negative cost variance of $5,000.
How to Interpret Cost Variance
- CV > 0: Favorable cost performance.
- CV < 0: Unfavorable cost performance.
- CV = 0: Cost performance is aligned with the earned value.
A negative CV does not automatically tell you what action the project manager should take. In an exam scenario, you may first need to determine why the variance occurred and what effect it has on the project.
2. Schedule Variance: SV = EV − PV
Schedule Variance compares the value of the work actually completed with the value of the work that was planned to be completed by that point.
Formula: SV = EV − PV
Using the example:
SV = $45,000 − $50,000 = −$5,000
How to Interpret Schedule Variance
- SV > 0: Earned progress is ahead of plan.
- SV < 0: Earned progress is behind plan.
- SV = 0: Earned progress is aligned with plan.
One important point is that Schedule Variance in earned value management is expressed in value terms. A Schedule Variance of −$5,000 does not mean the project is five days, five weeks, or another specific amount of calendar time behind schedule.
3. Cost Performance Index: CPI = EV ÷ AC
The Cost Performance Index measures cost efficiency.
Formula: CPI = EV ÷ AC
Using the example:
CPI = $45,000 ÷ $50,000 = 0.90
How to Interpret CPI
- CPI > 1.0: Favorable cost efficiency.
- CPI < 1.0: Unfavorable cost efficiency.
- CPI = 1.0: Cost efficiency is aligned with plan.
A CPI of 0.90 means that the project is earning approximately $0.90 of budgeted value for every $1.00 spent.
4. Schedule Performance Index: SPI = EV ÷ PV
The Schedule Performance Index compares earned progress with planned progress.
Formula: SPI = EV ÷ PV
Using the example:
SPI = $45,000 ÷ $50,000 = 0.90
How to Interpret SPI
- SPI > 1.0: Earned progress is ahead of plan.
- SPI < 1.0: Earned progress is behind plan.
- SPI = 1.0: Earned progress is aligned with plan.
Like Schedule Variance, SPI is an earned value indicator. An SPI of 0.90 should not be interpreted as meaning the project is a specific number of days behind schedule.
5. Estimate at Completion When Current Cost Performance Continues
Estimate at Completion forecasts the project’s total final cost.
There is more than one EAC formula because the appropriate calculation depends on what you expect to happen during the remaining work.
If current cost efficiency is expected to continue:
EAC = BAC ÷ CPI
Using the example:
EAC = $100,000 ÷ 0.90 = approximately $111,111
If cost efficiency continues at the same rate, the project is forecast to cost approximately $111,111 when complete.
The important part of an EAC question is understanding the assumption. Do not simply use the first EAC formula you remember.
6. Estimate at Completion When Future Work Follows the Original Plan
Sometimes the cost variance that has already occurred is considered atypical and is not expected to continue.
If the remaining work is expected to be completed according to the original cost plan:
EAC = AC + (BAC − EV)
Using the example:
EAC = $50,000 + ($100,000 − $45,000)
EAC = $105,000
This calculation assumes that the project’s previous cost performance will not continue and that the remaining work can be completed according to the original cost expectation.
7. Estimate at Completion Using CPI and SPI
If both current cost and schedule performance are expected to affect the remaining work, a forecast can incorporate both CPI and SPI.
EAC = AC + (BAC − EV) ÷ (CPI × SPI)
Using the example:
EAC = $50,000 + ($55,000 ÷ (0.90 × 0.90))
EAC = approximately $117,901
This forecast is more pessimistic than the previous examples because both cost and schedule efficiency are affecting the remaining work.
Do not use this formula automatically just because a question provides CPI and SPI. The scenario should support the assumption that both factors are relevant to the cost of completing the remaining work.
8. Estimate to Complete: ETC = EAC − AC
Estimate at Completion and Estimate to Complete answer different questions.
EAC asks what the entire project is expected to cost.
ETC asks how much more you expect to spend from this point forward.
Formula: ETC = EAC − AC
If EAC is $111,111 and the project has already spent $50,000:
ETC = $111,111 − $50,000 = $61,111
The project is therefore expected to require approximately another $61,111 to complete.
9. Variance at Completion: VAC = BAC − EAC
Variance at Completion compares the original approved budget with the current forecast of the project’s final cost.
Formula: VAC = BAC − EAC
Using an EAC of $111,111:
VAC = $100,000 − $111,111 = −$11,111
How to Interpret VAC
- Positive VAC: The project is forecast to finish under budget.
- Negative VAC: The project is forecast to finish over budget.
- VAC = 0: The project is forecast to finish at the original BAC.
Do not confuse VAC with Cost Variance. CV describes current cost performance, while VAC compares the total approved budget with the forecast total cost at completion.
10. To-Complete Performance Index Based on BAC
The To-Complete Performance Index asks how efficiently the remaining work must be performed to achieve a particular financial target.
If the project is still expected to finish within the original BAC:
TCPI = (BAC − EV) ÷ (BAC − AC)
Using the example:
TCPI = ($100,000 − $45,000) ÷ ($100,000 − $50,000)
TCPI = $55,000 ÷ $50,000 = 1.10
A TCPI of 1.10 means the remaining work needs a cost-efficiency level of 1.10 for the project to finish at the original BAC.
In a scenario question, you may then need to consider whether that required level of performance is realistic.
11. To-Complete Performance Index Based on EAC
If the original BAC is no longer the realistic financial target and the project is working toward a revised Estimate at Completion, use the revised EAC in the denominator.
TCPI = (BAC − EV) ÷ (EAC − AC)
For example:
- BAC = $100,000
- EV = $45,000
- EAC = $111,111
- AC = $50,000
TCPI = $55,000 ÷ $61,111 = approximately 0.90
The key difference between the two TCPI formulas is the financial target being used. Read the scenario carefully to determine whether the target remains BAC or has been revised to EAC.
12. PERT Expected Duration
Three-point estimating can help account for uncertainty by using three possible estimates:
- O: Optimistic
- M: Most likely
- P: Pessimistic
The weighted PERT expected-duration formula is:
Expected Duration = (O + 4M + P) ÷ 6
Suppose an activity has:
- O = 4 days
- M = 6 days
- P = 10 days
The calculation is:
(4 + 4(6) + 10) ÷ 6 = 38 ÷ 6 = approximately 6.33 days
The most likely estimate receives four times the weight of the optimistic and pessimistic estimates.
13. PERT Standard Deviation
PERT can also be used to estimate uncertainty around the expected duration.
Standard Deviation = (P − O) ÷ 6
Using the previous example:
(10 − 4) ÷ 6 = 1 day
A larger standard deviation indicates greater uncertainty between the optimistic and pessimistic estimates.
14. PERT Variance
Variance is the square of the standard deviation.
Variance = ((P − O) ÷ 6)2
Using the same estimates:
((10 − 4) ÷ 6)2 = 12 = 1
Variance becomes particularly useful when analyzing uncertainty across multiple activities because variances can be combined when evaluating a path before converting the result back into a standard deviation.
15. Total Float
Total float shows how much scheduling flexibility an activity has before a delay affects the relevant project completion date or schedule constraint.
You can calculate it in either of two equivalent ways:
Total Float = LS − ES
or
Total Float = LF − EF
For example, if an activity has:
- ES = Day 9
- LS = Day 12
then:
Total Float = 12 − 9 = 3 days
An activity with zero total float is generally on the critical path in a basic critical path calculation.
What About Free Float?
Free float is related to total float, but the two measures answer different questions.
Free Float = Earliest ES of successor − EF of current activity
Free float measures how long an activity can be delayed without delaying the early start of an immediate successor.
Total float focuses on the effect on the overall project completion date or applicable schedule constraint, while free float focuses on the next activity.
Other Project Management Calculations You May Encounter
The 15 formulas above provide a practical core for PMP formula study, but they are not the only calculations used in project management.
Communication Channels
The number of potential communication channels among a group of people can be calculated using:
Communication Channels = n(n − 1) ÷ 2
where n is the number of people.
For a group of five people:
5(5 − 1) ÷ 2 = 10 communication channels
Expected Monetary Value
Expected Monetary Value can be used in quantitative risk analysis.
EMV = Probability × Impact
If a threat has a 30% probability and a negative financial impact of $20,000:
EMV = 0.30 × −$20,000 = −$6,000
This does not mean the project will definitely lose $6,000. It is the probability-weighted monetary value of the uncertain event.
How to Choose the Right PMP Formula
Instead of trying to memorize formulas as an isolated list, connect each calculation to the question it answers.
- Are we over or under budget? Think about CV or CPI.
- How does earned progress compare with planned progress? Think about SV or SPI.
- What is the project expected to cost when complete? Think about EAC.
- How much more money do we expect to spend? Think about ETC.
- How far is the forecast from the original budget? Think about VAC.
- How efficiently must the remaining work be performed? Think about TCPI.
- What duration should we use when estimates are uncertain? Think about PERT.
- How much flexibility does an activity have? Think about float.
When you see numbers in a PMP practice question, do not immediately start calculating.
First ask:
- What is the question actually asking me to determine?
- Which values have been provided?
- What assumptions does the scenario make?
- Which formula answers that specific question?
- What does the result mean for the project?
EAC Formulas: Understand the Assumption
Estimate at Completion is one of the areas where memorizing formulas without understanding them can cause problems.
Several equations calculate EAC because they make different assumptions about future project performance.
- BAC ÷ CPI: Use when current cost efficiency is expected to continue.
- AC + (BAC − EV): Use when the variance to date is considered atypical and the remaining work is expected to follow the original cost plan.
- AC + (BAC − EV) ÷ (CPI × SPI): Use when both current cost and schedule performance are expected to affect the remaining work.
On a scenario-based question, look for the assumption before choosing the equation.
Common PMP Formula Mistakes
Treating SPI as a Number of Days
SPI is an earned value performance ratio. An SPI of 0.90 does not mean the project is 10 days behind schedule.
Using the Wrong EAC Formula
Do not choose an EAC formula simply because you remember it. Determine what the scenario says about future performance.
Confusing CV and VAC
Cost Variance describes current cost performance. Variance at Completion compares BAC with the forecast EAC.
Confusing EAC and ETC
EAC represents expected total project cost. ETC represents the expected cost of the remaining work.
Memorizing Without Practicing Scenarios
Knowing that CPI = EV ÷ AC is helpful. Recognizing that a scenario is asking about cost efficiency is more important.
The current PMP exam emphasizes application and decision-making, so formula practice should include realistic situations rather than only flashcards or equation drills.
Do You Need More Than Formula Practice?
Formulas represent only one part of PMP preparation. The current exam also covers leadership, stakeholders, project delivery, business environment, predictive, adaptive, and hybrid approaches, as well as topics such as value, outcomes, AI, and sustainability.
If you still need your required 35 hours of project management training or want structured instruction before moving into full exam simulation, Brain Sensei’s PMP exam prep course combines self-paced training with an included exam simulator and more than 2,200 practice questions.
PMP Formula Study Checklist
Before considering your formula review complete, make sure you can:
- Define PV, EV, AC, BAC, EAC, and ETC.
- Calculate and interpret Cost Variance.
- Calculate and interpret Schedule Variance.
- Explain what CPI above, below, and equal to 1.0 means.
- Explain what SPI above, below, and equal to 1.0 means.
- Choose an EAC formula based on the assumptions in the scenario.
- Explain the difference between EAC and ETC.
- Explain the difference between CV and VAC.
- Calculate TCPI against BAC or a revised EAC.
- Use optimistic, most likely, and pessimistic estimates in PERT.
- Calculate PERT standard deviation and variance.
- Calculate total float.
- Interpret what a calculation means instead of stopping after the arithmetic.
PMP Exam Formula FAQs
Do You Need to Memorize PMP Formulas?
PMI does not publish an official list of formulas that every PMP candidate must memorize. However, understanding common project management calculations can help you recognize and solve calculation-based or performance-analysis scenarios during preparation.
How Many Formula Questions Are on the PMP Exam?
PMI does not publish a guaranteed number or percentage of formula questions on the current PMP exam. Be cautious about study resources that claim an exact number without a current authoritative PMI source.
What Are the Most Important Earned Value Formulas?
Useful earned value calculations include CV, SV, CPI, SPI, EAC, ETC, VAC, and TCPI. Together, they help you evaluate current performance and forecast where a project may finish financially.
What Does a CPI Greater Than 1 Mean?
A CPI greater than 1.0 indicates favorable cost efficiency. A CPI below 1.0 indicates unfavorable cost efficiency, while a CPI of 1.0 indicates performance aligned with plan.
What Does an SPI Below 1 Mean?
An SPI below 1.0 indicates that earned progress is behind planned progress. It does not directly tell you the number of calendar days by which the project is behind.
Which EAC Formula Should You Use?
Choose the EAC formula that matches the assumption in the scenario. If current cost efficiency will continue, BAC ÷ CPI may apply. If future work is expected to follow the original plan, AC + (BAC − EV) may apply. If both cost and schedule efficiency are expected to affect the remaining work, the forecast may incorporate CPI and SPI.
What Is the Difference Between Total Float and Free Float?
Total float measures how long an activity can be delayed without delaying the applicable project completion date or constraint. Free float measures how long it can be delayed without delaying the early start of an immediate successor.
Is a PMP Formula Cheat Sheet Enough to Prepare for the Exam?
No. A cheat sheet can help you review calculations, but PMP preparation also requires understanding project management concepts, interpreting realistic scenarios, and deciding which action or calculation is appropriate in context.
Conclusion
PMP formulas become much easier when you stop treating them as a wall of equations and instead connect each calculation to the question it answers.
- CV and CPI help you understand cost performance.
- SV and SPI help you compare earned progress with the plan.
- EAC, ETC, and VAC help you forecast project cost.
- TCPI helps you evaluate the efficiency required to meet a financial target.
- PERT helps you account for uncertainty in estimates.
- Total float helps you understand schedule flexibility.
Once you understand those relationships, the next step is applying them to unfamiliar scenarios. That is more useful than memorizing equations without understanding when they should be used.
Practice With the PMP Exam Simulator
Sign-up for a 7-day free trial! Try the first two modules of Brain Sensei’s story-based PMP and CAPM Exam Prep courses and a mini practice exam and see how it all works
Conclusion
By understanding and mastering the 15 PMP exam formulas covered in this guide, you will be well-prepared to tackle calculation-based questions in the PMP exam. Additionally, we provide you with a comprehensive PMP cheat sheet that consolidates these formulas for quick reference. With the right knowledge, practice, and resources, you can confidently navigate the formula-related questions in the PMP exam and increase your chances of success.
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