Calculating the interest rate using the present value formula can at first seem impossible. However, with a little math and some common sense, anyone can quickly calculate an investment's interest ...

Ariel Courage is an experienced editor, researcher, and former fact-checker. She has performed editing and fact-checking work for several leading finance publications, including The Motley Fool and ...

Net present value (NPV) represents the difference between the present value of cash inflows and outflows over a set time period. Knowing how to calculate net present value can be useful when choosing ...

Julia Kagan is a financial/consumer journalist and former senior editor, personal finance, of Investopedia. Dr. Melody Bell is a personal finance expert, entrepreneur, educator, and researcher. Melody ...

Image source: Flickr user Ken Funakoshi. A perpetual annuity, also called a perpetuity, promises to pay a certain amount of money to its owner forever. A classic example would be that of a perpetual ...

To find an investment's interest rate, substitute price, face value, and duration into a formula. For T-bills, subtract purchase price from face value, divide by face value, adjust for term. Online ...