NPV Guide - Net Present Value
💵 What is Net Present Value (NPV)?
NPV is the difference between the present value of cash inflows and the present value of cash outflows over time. It tells you in dollar terms whether an investment creates or destroys value.
The NPV Formula
Simple Example
Interpretation: Positive NPV of $773 means the project creates value. At a 10% discount rate, you earn more than your cost of capital.
NPV Decision Rules
| NPV Result | Decision | Meaning |
|---|---|---|
| NPV > 0 (Positive) | Accept project | Creates value, exceeds hurdle rate |
| NPV = 0 | Neutral (breakeven) | Exactly meets required return |
| NPV < 0 (Negative) | Reject project | Destroys value, below hurdle rate |
NPV vs IRR: Key Differences
| Metric | NPV | IRR |
|---|---|---|
| Result format | Dollar amount ($45,000) | Percentage (18%) |
| What it shows | Absolute value created | Rate of return earned |
| Discount rate | You choose (cost of capital) | Calculated automatically |
| Scale consideration | Yes (bigger projects = bigger NPV) | No (% is scale-independent) |
| When to use | Final investment decision | Initial screening, comparison |
Understanding Discount Rate
The discount rate represents:
- Cost of capital: What you pay to borrow money
- Opportunity cost: What you could earn elsewhere
- Risk premium: Higher risk requires higher rate
Typical Discount Rates:
| Investment Type | Typical Rate |
|---|---|
| Government bonds (low risk) | 3-5% |
| Established business | 8-12% |
| New venture (medium risk) | 15-20% |
| Startup (high risk) | 25-35% |
$1,000 today vs $1,000 in 5 years:
At 10% discount rate, $1,000 in 5 years = $620.92 today
At 15% discount rate, $1,000 in 5 years = $497.18 today
Higher discount rates make future money worth less today.
Common Applications
Equipment Purchase:
Should we buy new machinery? NPV compares upfront cost to future productivity gains.
Real Estate Development:
Is this property development profitable? NPV considers all costs and future sale proceeds.
Business Acquisition:
Should we acquire this company? NPV values future cash flows against purchase price.
Project Evaluation:
Which of 3 projects should we fund? Choose the one with highest positive NPV.
NPV assumes:
- Cash flows occur exactly as predicted
- Discount rate remains constant
- Cash can be reinvested at discount rate
- Doesn't account for flexibility or real options
Use NPV as one tool, not the only decision factor.
🔢 Calculating NPV Step-by-Step
Example: Manufacturing Equipment
Scenario: Company considering $150,000 machine with 5-year life
Cash Flows:
| Year | Cash Flow |
|---|---|
| 0 (Today) | -$150,000 |
| 1 | $30,000 |
| 2 | $35,000 |
| 3 | $45,000 |
| 4 | $60,000 |
| 5 | $85,000 |
Discount rate: 10%
Step 1: Calculate Present Value of Each Cash Flow
Step 2: Sum All Present Values
Step 3: Subtract Initial Investment
Impact of Discount Rate
Same project, different discount rates:
| Discount Rate | NPV | Decision |
|---|---|---|
| 8% | $44,956 | Accept (strong positive) |
| 10% | $33,767 | Accept (positive) |
| 15% | $10,533 | Accept (barely) |
| 17% | $1,031 | Marginal |
| 20% | -$11,452 | Reject (negative) |
Higher discount rates reduce NPV. At 20%, this project destroys value.
Comparing Multiple Projects
Three projects, $100k budget, which to choose?
| Project | Initial Cost | NPV at 12% | IRR |
|---|---|---|---|
| Project A | $50,000 | $18,500 | 24% |
| Project B | $80,000 | $31,200 | 19% |
| Project C | $100,000 | $35,000 | 17% |
Uneven Cash Flow Example
Software Development Project:
| Year | Cash Flow | Note |
|---|---|---|
| 0 | -$200,000 | Initial development |
| 1 | -$50,000 | More development (negative!) |
| 2 | $40,000 | Launch, slow uptake |
| 3 | $120,000 | Growing rapidly |
| 4 | $180,000 | Mature product |
| 5 | $200,000 | Peak revenue |
NPV Calculation at 15% discount rate:
Despite two years of negative cash flow, NPV is positive $68k. Project creates value.
🌍 Real-World NPV Examples
Decision: Open second restaurant location
Investment Required:
Projected Annual Cash Flows:
| Year | Revenue | Expenses | Net Cash Flow |
|---|---|---|---|
| 1 | $450,000 | $385,000 | $65,000 |
| 2 | $520,000 | $410,000 | $110,000 |
| 3-10 | Growing 5%/yr | Growing 3%/yr | $130k-$195k |
NPV at 18% (typical restaurant hurdle):
Decision: Proceed. Creates $135k in value at 18% hurdle rate.
Homeowner decision: Install solar panels
Costs:
Annual Savings:
NPV at 5% (homeowner's opportunity cost):
Decision: Install panels. Positive NPV of $13k means financial sense.
Evaluate: Purchase rental property
Purchase Details:
Annual Cash Flows (after mortgage, expenses):
NPV at 12% hurdle rate:
Decision: Reject. Negative NPV means return below 12% hurdle rate. Better opportunities exist.
🎯 Test Your Knowledge
Complete this 10-question quiz on NPV