Compound interest calculator
Enter a starting amount, a monthly contribution, a yearly return and a number of years. The calculator shows how much of the final balance is your own money and how much is growth.
Investing calculators
Six small calculators that show the math behind common investing numbers. Every page explains the formula, works an example and lists what the tool leaves out. Results are illustrations, not forecasts.
Fund fee impact calculator
Two funds, the same investment, the same return before fees. The only difference is the yearly expense ratio — this calculator shows how far apart the ending values can drift.
Dividend yield calculator
Enter the share price, the size of each dividend payment and how often it is paid. Add your share count to see what that dividend would mean in dollars per year.
P/E ratio calculator
Two numbers in, two numbers out: the price-to-earnings ratio and the earnings yield. Here is what each one measures and where the ratio stops being useful.
Bond yield calculator
A bond's coupon rate is fixed, but its price is not. This calculator shows what that price does to the two yields people quote most: current yield and yield to maturity.
Retirement savings calculator
Enter your age, the age you plan to retire, what you have saved and what you add each month. The calculator shows a balance at retirement, then shrinks it back into today's dollars so the number means something.