A perpetuity is an annuity that has no end, or a stream of cash payments that continues forever. There are few actual perpetuities in existence (the United Kingdom (UK) government has issued them in the past; these are known and still trade as consols). A number of types of investments are effectively perpetuities, such as real estate and preferred stock, and techniques for valuing a perpetuity can be applied to establish price. Perpetuities are but one of the time value of money methods for valuing financial assets. Perpetuities are a form of ordinary annuities.

Eine ewige Rente (auch Perpetuität) ist eine Rente die aus dem Zinsertrag einer festverzinslichen Kapitalanlage gezahlt werden kann, ohne dass sich die Höhe des angelegten Kapitals ändert.

Perpetuïteit is een annuïteit waarvan de tijdsperiode oneindig is. Indien we dit wiskundig bekijken is het de limiet van de annuïteit naar oneindig.