An annuity is a series of payments made at equal intervals typically annually, monthly etc. In the U.S., an annuity product is sold usually by an insurance company to investors as a very secure, tax-deferred investment. It can provide a guaranteed interest rate. The earnings from the investment are deferred until the fund is paid from the account in each payment intervals. This calculator helps users to determine a fixed annuity income for a given period. Due to inflation, the fixed payment can be adjusted to the inflation rate. So each year the payout will increase to the amount of the inflation rate comparing to the previous years. For example, your receive $1000 in the previous year and current inflation rate is 3%. In the current year the payment is 1000*(1+3%) = 1030.

The payment type End means the investors will received the payment at the end of the each period and Beginning type means the payment will be made at the beginning of each period. With End payment type investors will typically receive more since the money stays in the investment one period longer.