Present value is the current value of a future stream of payments. In other words, it's the amount of money you would need to invest today to have a certain amount of money in the future.
For example, let's say you want to have $1,000 in one year. Assuming you earn 10% interest on your investment, you would need to invest $909 today to have $1,000 in one year. So, the present value of $1,000 is $909.
An annuity is a stream of equal payments that occur at regular intervals. The most common type of annuity is an ordinary annuity, which is when the payments are made at the end of each interval. For example, if you make monthly mortgage payments, those payments are an ordinary annuity. Car loans, student loans, and other installment loans are annuities.
There's also an annuity due, which is when payments are made at the beginning of each interval instead of the end. Annuities due are less common, but still important to understand because it impacts the present value calculation.
With that information, you can use this formula to calculate the present value of an annuity:
Let’s say you are going to receive $1,000 per year, for the next ten years, and the interest rate is 5%.
If you have a financial calculator, you can use its time value of money functions to calculate future value. To do this, you'll need to input the following information and then compute the future value:
When you solve for PV, you’ll get $7,721.73. If you had $7,721.73 today, you could invest it at 5% and withdraw $1,000 each year for ten years. The interest received each year on the $7,721.73 allows the balance to grow over time to fund the $10,000 of withdrawals.
In general, the present value of an annuity will be lower if you're receiving the payments over a longer period of time because you're forfeiting the opportunity to earn interest on your investment.
Remember, the present value is just one consideration when it comes to making financial decisions. You also need to consider the time value of money and your own personal circumstances. But if you're trying to calculate how much money you need to invest today to have a certain amount of money in the future, the present value formula is a good place to start.