What formulas do I need to know for the PMP exam?
The PMP exam tests Earned Value Management formulas most frequently: EV (Earned Value = BAC x % Complete), CV (Cost Variance = EV - AC), SV (Schedule Variance = EV - PV), CPI (Cost Performance Index = EV/AC), SPI (Schedule Performance Index = EV/PV), EAC (Estimate at Completion = BAC/CPI), and ETC (Estimate to Complete = EAC - AC). These formulas appear in numerical scenario questions and must be applied under time pressure.
The PMP exam contains approximately 15-20 quantitative questions that require applying formulas to project scenarios. While the current exam is scenario-heavy and tests judgment more than calculation, earned value management (EVM) calculations and project schedule formulas remain testable content that candidates must master.
The mistake most PMP candidates make is treating formulas as an afterthought. EVM questions reward precision: confusing EAC with ETC or misremembering whether a positive CPI means over or under budget can cost two to three questions. This formula sheet is designed for regular review in the final month before the exam.
Earned Value Management (EVM) Formulas
Foundation Values
| Term | Abbreviation | Definition | How to Calculate |
|---|---|---|---|
| Budget at Completion | BAC | Total authorized budget for work | Given in question |
| Planned Value | PV | Authorized budget for work scheduled to be done by now | Given or calculated from schedule |
| Earned Value | EV | Value of work actually completed to date | BAC x % Complete |
| Actual Cost | AC | Actual cost incurred for work done to date | Given in question |
"Earned Value is not what you spent. It is the budgeted cost of the work you completed. Confusing EV with AC is the single most common calculation error on PMP exams." -- PMP preparation instructor
Variance Formulas
| Metric | Formula | Positive = Good | Negative = Bad |
|---|---|---|---|
| Cost Variance (CV) | EV - AC | Under budget | Over budget |
| Schedule Variance (SV) | EV - PV | Ahead of schedule | Behind schedule |
| Cost Performance Index (CPI) | EV / AC | > 1 = under budget | < 1 = over budget |
| Schedule Performance Index (SPI) | EV / PV | > 1 = ahead of schedule | < 1 = behind schedule |
| To-Complete Performance Index (TCPI) | (BAC - EV) / (BAC - AC) | < 1 = achievable | > 1 = aggressive |
Memory trick for CV and SV: "Earned first" -- EV is always the first term subtracted. CV = EV - AC, SV = EV - PV.
Forecasting Formulas
| Metric | Formula | When to Use |
|---|---|---|
| EAC (assume CPI continues) | BAC / CPI | When current performance trend is expected to continue |
| EAC (assume remaining work on budget) | AC + (BAC - EV) | When remaining work will be done at original estimate |
| EAC (new estimate) | AC + ETC | When original estimate is no longer valid, use new estimate for remaining work |
| ETC (typical) | EAC - AC | Remaining work to complete at current performance |
| VAC (Variance at Completion) | BAC - EAC | Projected final overrun (negative) or underrun (positive) |
Schedule and Duration Formulas
PERT (Program Evaluation and Review Technique)
Three-point estimate (PERT Beta distribution):
PERT Estimate = (Optimistic + 4 x Most Likely + Pessimistic) / 6
PERT Standard Deviation:
Standard Deviation = (Pessimistic - Optimistic) / 6
PERT Variance:
Variance = Standard Deviation squared = [(Pessimistic - Optimistic) / 6]^2
Example: Task with O=2, ML=5, P=14
- PERT = (2 + 4x5 + 14) / 6 = (2 + 20 + 14) / 6 = 36/6 = 6 days
- SD = (14 - 2) / 6 = 12/6 = 2 days
- 68% confidence: 6 +/- 2 = 4 to 8 days
- 95% confidence: 6 +/- 4 = 2 to 10 days
- 99.7% confidence: 6 +/- 6 = 0 to 12 days
Triangular Distribution (Simpler Alternative)
Triangular Estimate = (Optimistic + Most Likely + Pessimistic) / 3
Communication and Stakeholder Formulas
Communication Channels
Formula: n(n-1)/2 where n = number of stakeholders
| Stakeholders | Communication Channels |
|---|---|
| 2 | 1 |
| 5 | 10 |
| 10 | 45 |
| 15 | 105 |
| 20 | 190 |
Exam application: If project grows from 10 to 15 team members, new channels added = 105 - 45 = 60 additional channels.
Probability and Expected Monetary Value
Expected Monetary Value (EMV)
EMV = Probability x Impact
Used in decision tree analysis and risk reserve calculations.
Example:
- Risk A: 30% probability of $10,000 loss = -$3,000 EMV
- Risk B: 20% probability of $5,000 gain = +$1,000 EMV
- Net EMV = -$3,000 + $1,000 = -$2,000 (negative = net risk exposure)
Contingency Reserve
Contingency reserve is typically calculated as the sum of EMVs for identified risks, adjusted by risk appetite.
Float and Critical Path Concepts
Float (Total Float): Latest Finish - Earliest Finish, OR Latest Start - Earliest Start
Free Float: How much an activity can slip without affecting the early start of successor activities.
Critical Path: Sequence of activities with zero float from project start to finish.
Schedule Network Analysis formulas:
- Early Finish (EF) = Early Start (ES) + Duration - 1
- Late Start (LS) = Late Finish (LF) - Duration + 1
- Total Float = LS - ES OR LF - EF
"The critical path is not always the longest path in days. It is the path with zero float. In some network diagrams these are the same; in others with mandatory lags they can differ." -- PMP preparation course instruction
Process Improvement Formulas
Quality and Control Charts
Mean (Average): Sum of all values / Number of values
Standard Deviation: Indicates spread of data around mean
Control chart limits:
- +/- 1 sigma (standard deviation): 68.27% of data points
- +/- 2 sigma: 95.45% of data points
- +/- 3 sigma: 99.73% of data points
Rule of Seven: Seven consecutive data points on the same side of the mean indicates the process is out of control, even if all points are within control limits.
PMP Formula Quick Reference Card
| Formula | Full Expression |
|---|---|
| EV | BAC x % Complete |
| CV | EV - AC |
| SV | EV - PV |
| CPI | EV / AC |
| SPI | EV / PV |
| EAC | BAC / CPI |
| ETC | EAC - AC |
| VAC | BAC - EAC |
| TCPI | (BAC - EV) / (BAC - AC) |
| PERT | (O + 4ML + P) / 6 |
| SD | (P - O) / 6 |
| Comm channels | n(n-1) / 2 |
| EMV | Probability x Impact |
Frequently Asked Questions
How many formula questions are on the PMP exam? The current PMP exam contains approximately 15-20 quantitative questions out of 180 total. This represents roughly 10% of the exam. While formulas are not the majority of the test, getting all formula questions right adds meaningful points, and the EVM calculation sequence is predictable and fully preparable.
Do I need to memorize all EVM formulas or will they be provided? EVM formulas are not provided during the PMP exam. You must memorize them. The exam does provide scratch paper (erasable notepad), and most candidates immediately write down all formulas before reading the first question. Practice writing the full formula set from memory in under two minutes.
Is the PERT formula always tested or just sometimes? PERT three-point estimates appear on the PMP exam with some regularity. Candidates occasionally encounter questions requiring them to calculate the PERT estimate and standard deviation for an activity and then determine the probability range. Know both the PERT beta formula and the triangular distribution formula, as questions sometimes specify which to use.
References
- Project Management Institute. (2021). A Guide to the Project Management Body of Knowledge (PMBOK Guide) -- Seventh Edition. PMI.
- Project Management Institute. (2021). Practice Standard for Earned Value Management, Third Edition. PMI.
- Project Management Institute. (2021). PMP Examination Content Outline. https://www.pmi.org/certifications/project-management-pmp/earn-the-pmp/pmp-exam-preparation
- Heldman, K. (2021). PMP Project Management Professional Exam Cram. Pearson IT Certification.
- Phillips, J. (2021). PMP Project Management Professional Study Guide, Fifth Edition. McGraw-Hill Education.
- Mulcahy, R. (2018). PMP Exam Prep. RMC Publications.