is it bad drink three cups of coffee everyday?

How big are your 'cups'? My coffee mug holds about 2.5 regular size cups of coffee, so if I drank 3 of those, I'd consuming a lot of coffee in a day.

Here's some info I found in a Newsweek article:

"The U.S. Food and Drug Administration likewise suggests people not exceed more than 400 milligrams of caffeine each day." (400 milligrams of caffeine is equal to about four 8-ounce cups of coffee.)

So, it's probably fine unless you're also consuming caffeine from other beverages/products during the day.

I usually drink two 12oz cups of coffee a day - but I drink them black

depends on what else you drink..... it is the caffeine that is the trouble maker... but three cups of coffee alone during the day.... not usually a problem... I usually drink two 20 oz mugs a day....

Depends how big the cups are and how strong the coffee.