How dividend yield works
Dividend yield is this year's dividends divided by today's share price. A company paying $0.45 a quarter on a $50 stock yields 3.6%: four payouts make $1.80 a year, and $1.80 is 3.6% of $50. The calculator does that arithmetic for any price, payout, and frequency, and shows what it means in dollars for the shares you hold.
Yield moves when either number moves. A falling share price raises the yield without the company paying a cent more, which is why a suddenly cheap stock can look suddenly generous. Check whether the yield rose because the dividend grew or because the price fell; only one of those is good news.