What's the difference between a BR30 and a PAR30 bulb?

BR30 bulbs throw a wide, soft flood and are the standard fit for 5- and 6-inch recessed cans and general room lighting. PAR (PAR30/PAR38) bulbs use a reflector that produces a tighter, brighter beam, which is why they're favored for accent lighting, track heads, and outdoor flood applications. If you're filling ceiling cans for everyday light, BR30 is usually the right shape; if you want a focused spot or an outdoor-rated flood, look to PAR.