Earnings calculator
Put in your principal, the APR, and how many days you plan to leave it, and get a rough sense of the interest. Flip between "simple interest" and "daily compound" to see the gap. This is only to give you a ballpark; the real rate floats, what actually lands follows Binance's page, and crypto earn is not principal-protected.
A rough estimate from the APR you entered. Binance Flexible often uses tiered rates (the high APR covers only a small first slice of your balance), and APR floats with the market, so the real result usually won't match this exactly.
What this shows is the ideal case where "the rate never changes." In reality Flexible APR moves every day, Locked fixes the rate but early redemption forfeits interest, and products priced in volatile coins pile price swings on top. Treat it as a rough order of magnitude, not a promise. For how the math works, see the difference between APR and APY.