Yield answers the investor's bluntest question: for every dollar I put in, how many cents come back to me each year? A $50 stock paying $2 in annual dividends yields 4 percent; a $1,000 bond paying $60 in coupons yields 6 percent. The concept is identical across stocks, bonds, and rental property -- income divided by price -- which makes yield the universal language for comparing income investments.

The page reduces the whole idea to a ratio: give it annual income and price, and the Result field reports the yield. Enter the annual income the investment produces in the Variable A field and the price you pay in Variable B -- $2 of dividends and a $50 share price, for instance -- and the Result gives the yield. Because it is a ratio, yield moves opposite to price: when that stock drops to $40 with the dividend intact, the yield jumps to 5 percent, which is why falling markets quietly put income investments on sale.

Chasing the highest yield is the classic trap. A 12 percent dividend yield usually means the market expects a dividend cut, just as a junk bond's 9 percent yield prices in real default risk. Use the tool to compare yields across candidates, then ask why the highest one is highest before letting it seduce you.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Yield Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.