What is the difference between a PAR and R/BR bulb?
PAR 20 , 30 and 38 and BR (or R) 20, 30 and 40 despite their similar names are quite different. Though they bear some similarities, understanding their differences will help you make better decisions about which one of these bulbs works best for your needs. They both share almost all of the same features that come with LED Light Bulbs, and therefore you only need to know the following difference between the two types.
R (Reflector) / BR (for bulged reflector) bulbs are lamps with “wide flood” beam angles, which means that they provide more than a 45° (typically 120°) angle when lighting an area. Use BR bulbs when a broad pattern of ambient light is needed such as down a hallway or over a kitchen countertop. BR bulbs also work best in recessed downlights or "pot lights" as they provide the best wide angle illumination.
PAR (short for Parabolic Aluminized Reflector) bulbs are lamps with "spot light" features, meaning that they provide a beam spread that is typically lower than 45°. Use PAR bulbs when attempting to put a focused beam of light on an object such as in track lighting or illuminating artwork. PAR spot lights also work great as outdoor security lighting.