FIN435 • Financial Management • Chapter 11

Capital Budgeting

What capital budgeting is, why firms use it, when to use each tool, and how to evaluate projects with NPV, IRR, MIRR, PI, payback, discounted payback.
Decision rule chapter Time value of money Project selection Excel + calculator support

What is capital budgeting?

Capital budgeting is the process of deciding whether a long-term investment project should be accepted or rejected. Typical examples include buying equipment, opening a new location, launching a product line, upgrading technology, or replacing an old machine.

Main question: Does this project create value for the firm?
  • It focuses on future cash flows, not accounting profit.
  • It uses the time value of money.
  • It helps firms compare projects consistently.
  • It connects project choice to shareholder value.

Why do we study it?

Capital budgeting matters because large investment decisions can help or hurt a firm for many years. A bad project can lock a company into weak returns, while a good project can add value immediately.

Why it matters
Value
Main lens
Cash flow
Core idea
Discounting
In practice, managers use capital budgeting when the decision is large, long-term, risky, and difficult to reverse.

How do we evaluate projects, and when do we use each tool?

NPV

Use when: you want the best value-creation decision.

  • Best for mutually exclusive projects
  • Directly measures value added in dollars
  • Usually the preferred decision rule

IRR

Use when: you want a return expressed as a percentage.

  • Popular and intuitive
  • Can conflict with NPV
  • Can mislead with unusual cash-flow patterns

MIRR

Use when: you want an improved version of IRR.

  • Uses a finance rate and reinvestment rate
  • Often more realistic than IRR
  • Good supplement to NPV

Payback

Use when: liquidity and speed of recovery matter.

  • Simple and fast
  • Ignores later cash flows
  • Useful as a rough screening tool

Discounted payback

Use when: you want payback plus time value of money.

  • Better than regular payback
  • Still ignores later cash flows
  • Good secondary measure

PI

Use when: capital is rationed or projects have different sizes.

  • Relative measure
  • Good for ranking efficiency
  • Do not let it override NPV for mutually exclusive choices
Bottom line: If NPV and IRR disagree for mutually exclusive projects, the usual rule is to follow NPV.

Excel syntax and classroom formulas

1) NPV in Excel
Syntax: NPV(rate, value1, value2, ...)

Excel discounts the cash flows from year 1 onward, so year 0 is usually added separately.

Example: =NPV(11%, 350, 350, 350) - 800
Reminder: the cash flows inside NPV() must be equally spaced and listed in the correct order.
2) IRR in Excel
Syntax: IRR(values, guess)
Example: =IRR({-800,350,350,350}) =IRR({-90000,132000,100000,-150000},0.10) =IRR({-90000,132000,100000,-150000},0.40)

IRR is the discount rate that makes NPV equal to zero. When cash flows are non-conventional, Excel's guess can matter. A default guess of 10% often finds the lower root, while a higher guess such as 40% can find the second IRR.

3) MIRR in Excel
Syntax: MIRR(values, finance_rate, reinvest_rate)
Example: =MIRR(B2:E2, 11%, 11%)

MIRR separates the borrowing cost from the reinvestment rate and avoids some of the problems that traditional IRR can create.

4) PI formulas
PI = Present value of inflows / |CF0|
PI = 1 + NPV / |CF0|

Method summary table

Method Equation / idea Ease of use Potential problems Popularity
NPV Σ(CF / (1+r)n) − Initial investment Easy in Excel Sensitive to cash-flow estimates and discount rate Very popular because it focuses on value creation
IRR Discount rate that makes NPV = 0 Easy in Excel Assumes reinvestment at IRR; can mislead with multiple sign changes Very popular because it gives a % return
MIRR Uses finance rate + reinvestment rate Moderate Less familiar to some users Used less often, but helpful in tricky cases
Payback Time needed to recover initial investment Very easy Ignores cash flows after payback Common for quick screening
PI PV inflows / Initial investment Easy Relative measure; can be less clear for mutually exclusive projects Used less than NPV and IRR, but still useful

Worked example using the JU capital budgeting calculator

Example: a new store near JU plans to spend $10,000 today, operate for 4 years, and then close at the end of Year 4. Assume the store generates these annual net cash inflows: $3,000, $3,500, $4,000, and $4,500. The firm's WACC is 10%.

Inputs to enter in the calculator

Item Value
WACC / required return10%
Initial investment (Year 0)-$10,000
Year 1 cash flow$3,000
Year 2 cash flow$3,500
Year 3 cash flow$4,000
Year 4 cash flow$4,500
Cash flow stream: -10000, 3000, 3500, 4000, 4500
This is an easy 4-year project example for students: the business opens now, earns cash for four years, and closes at the end of Year 4.

Results students should see

Measure Result Meaning
NPV $1,698.65 Positive NPV means the project adds value.
IRR 17.09% IRR is above the 10% WACC, so this supports accepting the project.
MIRR 14.40% MIRR is also above the 10% WACC, so the project still looks good.
PI 1.170 For every $1 invested, the project creates about $1.17 in present value inflows.
Payback 2.875 years The initial cost is recovered before the end of Year 3.
Discounted payback 3.4473 years After considering time value of money, recovery still happens before the 4-year project ends.
Decision Accept project All major measures support acceptance.
At a 10% required return, the present value of inflows is greater than the $10,000 cost, so the project appears financially attractive.
Step-by-step explanation for students (click to expand)
  • NPV: discount each future cash flow at 10%, add them up, and subtract the $10,000 initial cost.
  • IRR: find the discount rate that makes NPV equal to zero. Here, that rate is about 17.09%.
  • MIRR: this improves IRR by using finance and reinvestment rates more realistically.
  • PI: compare the present value of inflows to the initial cost. A PI above 1 means accept.
  • Payback: shows how quickly the original investment is recovered.
  • Discounted payback: does the same thing, but after discounting the cash flows.
At 10%: PV(Year 1) = 3000 / 1.10 = 2727.27 PV(Year 2) = 3500 / 1.10^2 = 2892.56 PV(Year 3) = 4000 / 1.10^3 = 3005.26 PV(Year 4) = 4500 / 1.10^4 = 3073.56 Total PV of inflows = 11698.65 NPV = 11698.65 - 10000 = 1698.65
Classroom takeaway: because NPV is positive and both IRR and MIRR are above the 10% WACC, this project should be accepted.

Single-project calculator (Part I classroom example)

Enter the WACC and the project cash flows. The page computes NPV, IRR, MIRR, PI, payback period, and discounted payback period. The default values match the classroom example.

Default guess is 10%. For multiple IRRs, try a higher guess such as 40% to find the second root.
Open JU calculator
How payback is computed
Payback: Add undiscounted cash inflows until the initial outlay is recovered. Discounted payback: First discount each inflow by WACC, then add the present values until the initial outlay is recovered.
How the IRR guess works
Normal cash flows: A project usually has one IRR, so the guess does not matter much. Non-conventional cash flows: If the signs change more than once, there may be more than one IRR. A guess near 10% often finds the lower IRR. A higher guess such as 40% can find the second IRR.

Results

NPV:

IRR:

All IRRs found (if multiple):

MIRR:

PI:

Payback period:

Discounted payback:

Decision by NPV:

Math equations + Excel formulas for IRR and MIRR
NPV = ∑ [ CFt / (1 + r)t ]
IRR solves: 0 = ∑ [ CFt / (1 + IRR)t ]
MIRR = ( FV of positive cash flows at reinvestment rate / |PV of negative cash flows at finance rate| )1/n − 1
PI = PV of inflows / |CF0| = 1 + NPV / |CF0|
Payback = years before full recovery + (unrecovered amount / current year cash flow)
Discounted payback = years before PV recovery + (unrecovered amount / current year discounted cash flow)
Excel IRR syntax: =IRR(values, guess) Excel MIRR syntax: =MIRR(values, finance_rate, reinvest_rate)

IRR vs. MIRR on the current input cash flows

IRR uses one internal rate for the whole project. MIRR uses two rates: a finance rate for negative cash flows and a reinvestment rate for positive cash flows. In the MIRR picture, negative cash flows move left to today and positive cash flows move right to the end.

IRR one-rate idea MIRR two-rate idea Positive cash flow Negative cash flow

Current-input math work

Interpretation: IRR forces the project into one rate. MIRR separates the financing side from the reinvestment side, so it is often easier to explain and usually gives one cleaner answer.
Video: What is MIRR? How does it address the challenges of internal rate of return?
Live current-input timeline
Year Cash flow Discounted cash flow Cumulative cash flow Cumulative discounted cash flow

Mutually exclusive projects (Part II)

When projects are mutually exclusive, choosing one means giving up the other. In that setting, the standard classroom rule is to choose the project with the higher NPV.

Question 1: Projects S and L
YearProject SProject L
0-$1,100-$2,700
1$550$650
2$600$725
3$100$800
4$100$1,400
Key idea: if one manager chooses by IRR and another chooses by NPV, the value forgone is the difference between the NPV of the project actually chosen and the highest available NPV.
Question 2: Project A vs. Project B
PeriodProject AProject B
0-500-400
1325325
2325200
  • Crossover rate: 11.8%
  • If required return is 10%: NPV of A is slightly higher than NPV of B.
  • If required return is 13%: NPV of B is higher than NPV of A.
  • Mutually exclusive rule: choose the project with the higher NPV at the required return.
  • If independent: choose both if both have positive NPV.

Math work for the crossover rate

NPV(A) = -500 + 325/(1+r) + 325/(1+r)2 NPV(B) = -400 + 325/(1+r) + 200/(1+r)2 Set the two NPVs equal to find the crossover rate: -500 + 325/(1+r) + 325/(1+r)2 = -400 + 325/(1+r) + 200/(1+r)2 -100 + 125/(1+r)2 = 0 125/(1+r)2 = 100 (1+r)2 = 1.25 1+r = √1.25 r = √1.25 - 1 = 0.1180 = 11.80%
The crossover rate is the discount rate where the two projects have the same NPV. Below that rate, one project can have the higher NPV; above that rate, the ranking can switch.

NPV profiles and the crossover rate

Non-conventional cash flow: why IRR can give two answers but MIRR gives one

Non-conventional cash flows change sign more than once. That can make the NPV profile cross zero more than once, which means IRR can produce more than one economically meaningful answer.

YearCash flow
0-$90,000
1$132,000
2$100,000
3-$150,000

IRR math work: why there are two IRR solutions

Set NPV equal to zero: 0 = -90,000 + 132,000/(1+r) + 100,000/(1+r)2 - 150,000/(1+r)3 Multiply both sides by (1+r)3: 0 = -90,000(1+r)3 + 132,000(1+r)2 + 100,000(1+r) - 150,000 This equation has two positive solutions for r: IRR1 ≈ 10.11% IRR2 ≈ 42.66% Excel can find both if you change the guess: =IRR({-90000,132000,100000,-150000},0.10) → 10.11% =IRR({-90000,132000,100000,-150000},0.40) → 42.66%
Because the cash-flow signs switch more than once, the NPV curve crosses zero twice. That is why there are two IRR answers in this example.

MIRR math work: move negatives left and positives right

Use finance rate = 15% and reinvestment rate = 15%. Step 1: Move negative cash flows to year 0: PV of negatives = 90,000 + 150,000/(1.15)3 PV of negatives = 188,627.43 Step 2: Move positive cash flows to the end of year 3: FV of positives = 132,000(1.15)2 + 100,000(1.15) FV of positives = 289,570.00 Step 3: Solve for one rate over 3 years: MIRR = (289,570.00 / 188,627.43)1/3 - 1 MIRR ≈ 15.36% Excel: =MIRR({-90000,132000,100000,-150000},15%,15%) → 15.36%
Try these cash flows in the calculator above: -90000, 132000, 100000, -150000. Use Guess 10% to find the first IRR and Guess 40% to find the second IRR.

NPV profile: the curve crosses zero twice

MIRR timeline: negatives move left, positives move right

Positive cash flow moved to the right Negative cash flow moved to the left Single MIRR result

Class video of Chapter 11 case study

Students can click the button or watch directly on the page.

Homework / case study

The case study questions are due with the second midterm exam. Use the Excel file and the class video together.

Suggested workflow:
  1. Read the project cash flows carefully.
  2. Compute NPV first.
  3. Then compute IRR, MIRR, PI, payback, and discounted payback.
  4. If there is a conflict for mutually exclusive projects, follow NPV.