PMP Formulas Cheat Sheet
You do not need to be a mathematician to pass the PMP exam, but a small set of formulas shows up often enough that memorizing them is worth the effort. More importantly, the exam usually tests whether you understand what a number means, not just whether you can plug values into a formula. This guide covers the formulas that earn the most points and how to read them.
Earned value management (EVM)
Earned value is the most tested formula family. Three base values feed everything else:
- Planned Value (PV): the budgeted cost of work scheduled to be done by now.
- Earned Value (EV): the budgeted cost of work actually completed.
- Actual Cost (AC): the real money spent to complete that work.
From those three, you derive variances and indexes:
| Formula | Meaning | How to read it |
|---|---|---|
| CV = EV − AC | Cost Variance | Negative = over budget |
| SV = EV − PV | Schedule Variance | Negative = behind schedule |
| CPI = EV ÷ AC | Cost Performance Index | Below 1.0 = over budget |
| SPI = EV ÷ PV | Schedule Performance Index | Below 1.0 = behind schedule |
A quick way to remember direction: for variances, negative is bad; for indexes, below 1.0 is bad. If a question says CPI is 0.85, the project is spending 85 cents of value for every dollar spent, so it is over budget.
Forecasting (EAC and friends)
When a question asks "how much will this project cost in total now," it is testing forecasting:
| Formula | When to use |
|---|---|
| EAC = BAC ÷ CPI | Current cost performance will continue |
| EAC = AC + (BAC − EV) | The remaining work will go as originally planned |
| ETC = EAC − AC | Estimate left to finish |
| VAC = BAC − EAC | Variance at completion |
BAC is the Budget at Completion, the original total budget. The trick is reading the scenario to decide which EAC assumption applies.
Communication channels
A favorite quick question: how many communication channels exist in a team of n people?
Channels = n × (n − 1) ÷ 2
For 6 people that is 6 × 5 ÷ 2 = 15. The exam often asks how many channels are added when the team grows, so calculate both sizes and subtract. Adding one person to a team of 6 (15 channels) to make 7 (21 channels) adds 6 channels.
Three-point estimation (PERT)
When a task has uncertainty, PMP uses three estimates: optimistic (O), most likely (M), and pessimistic (P).
| Formula | Name |
|---|---|
| (O + 4M + P) ÷ 6 | Beta / PERT estimate |
| (O + M + P) ÷ 3 | Triangular estimate |
| (P − O) ÷ 6 | Standard deviation |
The beta formula weights the most likely value heavily, which is why it is the default in most questions.
Procurement and value
A few smaller formulas appear in cost and procurement questions. Point of Total Assumption (PTA) shows up in fixed-price incentive contracts, and present value or benefit-cost ratio appears in project selection. For most candidates these are lower priority than EVM and communication channels.
How to study formulas
Do not memorize formulas in isolation. Practice them inside scenario questions so you learn to recognize which formula a question is really asking for. A question that mentions "we have spent more than planned for the work done" is a CV or CPI question even if it never uses the word variance. On PMP Quiz you can filter practice toward calculation-style questions and review each one until the meaning, not just the math, is automatic.