Glossary term
Ordinary Annuity
An ordinary annuity is a stream of equal payments made at the end of each period, such as the end of each month or year.
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What Is an Ordinary Annuity?
An ordinary annuity is a series of equal payments made at the end of each period. The period might be a month, quarter, or year. The timing is the key: payments happen after the period has passed, not at the beginning.
The term is used in finance math, retirement-income analysis, loan schedules, leases, and insurance products. It is different from an annuity due, where each payment is made at the beginning of the period.
Key Takeaways
- An ordinary annuity has equal payments at the end of each period.
- Payment timing affects present value and future value calculations.
- An annuity due is similar, but payments occur at the beginning of each period.
- The concept is a math structure and should not be confused with a specific insurance product.
Payment Timing
Ordinary annuity math assumes the first payment occurs one full period from the valuation date. If monthly payments are involved, the first payment is at the end of the first month. If annual payments are involved, the first payment is at the end of the first year.
That timing makes an ordinary annuity less valuable today than an otherwise identical annuity due, because each payment is received one period later.
Payment Stream | Payment Timing | Present Value Effect |
|---|---|---|
Ordinary annuity | End of each period. | Lower than an annuity due with the same terms. |
Annuity due | Beginning of each period. | Higher because each payment arrives sooner. |
Uneven cash flows | Payments vary by amount or timing. | Requires separate discounting rather than a simple annuity formula. |
Present Value Formula
The present value of an ordinary annuity estimates what a fixed stream of future end-of-period payments is worth today.
In this formula, PV is present value, PMT is the payment each period, r is the discount rate per period, and n is the number of payments. The rate and payment period must match. Monthly payments require a monthly rate; annual payments require an annual rate.
Where It Shows Up
Ordinary annuity logic appears whenever equal payments are made at the end of regular periods. Examples include many loan-payment calculations, retirement drawdown illustrations, bond coupon timing assumptions, and certain pension or annuity income projections.
In consumer finance, the distinction matters because a one-period timing difference can change value. A payment received today can be invested or used immediately. A payment received later must be discounted back to today.
The Bottom Line
An ordinary annuity is a fixed payment stream with payments at the end of each period. The concept is simple, but the timing matters because end-of-period payments are worth less today than otherwise identical payments made at the beginning of each period.