Growing annuity
A growing annuity is a finite series of payments that grow at a constant rate g each period. Its present value is PV = C1 / (r - g) x (1 - ((1 + g) / (1 + r))^n), where C1 is the first payment. It is a growing perpetuity cut off after n payments.
Syntax
PV = C1 / (r - g) x (1 - ((1 + g) / (1 + r))^n) (if r = g: PV = n x C1 / (1 + r))| Part | What it is |
|---|---|
C1 | First payment, one period from now |
r | Discount rate per period |
g | Growth rate of the payment per period |
n | Number of payments |
Examples
First payment 100, growing 3% a year for 5 years, r = 8%
PV = 100 / (0.08 - 0.03) x (1 - (1.03 / 1.08)^5)Result: PV = 422.04
Rent of 1,000 next year, rising 2% a year for 10 years, r = 7%
PV = 1,000 / 0.05 x (1 - (1.02 / 1.07)^10)Result: PV = 7,606.50
Check with g = 0: 100 for 3 years at 5%
PV = 100 / 0.05 x (1 - (1 / 1.05)^3)Result: PV = 272.32 (same as the level annuity)
Common mistakes
- Using the current payment instead of the first future payment C1; if the payment just made was 100 and growth is 3%, C1 is 103.
- Dividing by zero when r equals g; use PV = n x C1 / (1 + r) in that case.
- Mixing an annual growth rate with a monthly discount rate; both must be per the same period.
Practice Growing annuity
These drills check your answer on live data, free, no account needed.
- Growing annuityA pension pays $13,000 at the end of the first year, and each later payment is 1% larger than the one before. There are 24 payments in all. At a discount rate of 7%, what is the pension worth today?
- Growing perpetuityA rental property's net cash flow next year will be $8,000, and it is expected to grow 1% a year forever. At a required return of 9%, what is the property worth today?
Questions
What is the future value of a growing annuity?
FV = C1 / (r - g) x ((1 + r)^n - (1 + g)^n). For the first example: 100 / 0.05 x (1.08^5 - 1.03^5) = 620.11, which equals the PV of 422.04 compounded 5 years at 8%.
Can I do a growing annuity in Excel?
There is no built-in function. Either type the formula directly or list the growing payments in a column and use =NPV(r, range).
Related
- PerpetuityA perpetuity pays a fixed amount forever and is worth PV = C / r. The growing perpetuity formula C1 / (r - g), examples for preferred stock and dividends.
- Present value of an annuityHow to find the present value of equal payments with PV = PMT x (1 - (1 + r)^-n) / r. Worked examples, Excel PV and why this is the loan formula in disguise.
- Annuity formula (future value)The future value of an ordinary annuity is PMT x ((1 + r)^n - 1) / r. Examples for yearly and monthly deposits, the Excel FV function and common errors.
- NPV (net present value)Net present value is the sum of discounted cash flows minus the initial investment. Examples at 10% and 8%, the accept rule, Excel NPV and the sign mistake.
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