Here at LTG Lighting we understand that our average customers may not be familiar with lighting terminology. We decided to write this guide to try and make your buying experience as easy as possible. We promise we will try and explain this topic as easier as possible.

First let's beginning by deciding what type of reflector lamp you will need. Do you need a spot beam or flood beam?

Spot vs. Flood

Note: A reflector lamp has either a spot or flood beam, depending on its size.

Spot Beam: Outputs a narrow beam of light, typically less than 45 degrees wide. Most of the light from a spot beam is concentrated onto a relatively small area producing a bright spot which makes them ideal for retail displays, residential or commercial showcases and exhibits. They are commonly used with recessed trims and track lighting.

Flood Beam: Outputs a wider beam of light covering a larger area, typically 120 degrees wide. Floodlights provide a great deal of light to the area in which they are placed. They are ideally used in homes, gardens and commercially used in stadiums, stages and outside businesses or homes as a security measure to discourage criminals.

Now that you know the difference between spot and flood beams I'm sure you have even more questions like how wide would the beam spread be from a certain distance away? Continue reading this guide and refer to the beam spread chart below and all your questions will soon be answered.

Measuring Beam Spread

Note: Beam spread measures the spread of light from a reflectorized light source. Popular varieties of these lamps include PAR, MR, BR, ER and R.

To find the width of a beam from a given distance, use this mathematical formula:

Angle of Beam X .018 X Distance = Beam Spread

Let's say you were trying to figure out the beam spread of a 15 degree spotlight from a distance of 10 feet away, you would calculate the follow.

15 X .018 X 10 = 2.7

Beam Spread Table

Don't like doing math? We understand that's why we created this beam spread table for you.

Lamp Manufacturers Beam Spread Terminology

Beam spreads are specified in two ways: by the number of degrees (for example, 40 degrees), or by the terminology used to describe the lighting effect produced by the reflector lamp. The National Electrical Manufacturers Association (NEMA) categorizes MR16 lamps as spot lamps or flood lamps. Some lamp manufacturers have created subcategories to better capture the ranges of beam angles. These subcategories are:

VNSP: Very narrow spot
NSP: Narrow spot
SP: Spot
NFL: Narrow flood
FL: Flood
WFL: Wide flood
VWFL: Very wide flood

Keep in mind that manufacturers may sometimes use these subcategories differently. This guide does not provide a comprehensive list of all products or manufacturers, but it shows examples of the beam spread and its terminology used by some lamp manufacturers. Lamp manufacturers such as EYE define beam spread as number of degrees only.