# How many lumens needed to light up a lawn using floodlights?

I'd like to add floodlights mounted to my house to light up my yard at night and I'm trying to figure out how bright a fixture I should buy. I've Googled a ton and found plenty of calculators to do the math, i.e. how high I'm mounting them and how much yard I'm trying to cover which results in this many foot-candles or lux. But those don't tell me anything about whether the results would make my lawn look dimly lit or like daylight.

Is there a set of rough guidelines or rules of thumb? I don't need to light it up like a night game at an athletic field but I want it brighter than just a security light. I need to be able to walk around with my dog and clearly see everything. I'd like to err on the side of more light, not less.

The lawn I'm trying to cover is 65x80 feet (about 20x25 meters) and I'd mount the lights about 20 feet high.

• en.wikipedia.org/wiki/Lux There's a table in there that gives examples of how brightly a surface is illuminated based on the lux of that surface. Should be sufficient. Looks like 20-50 lux should be in your ballpark. Apr 26, 2017 at 16:13
• It's maybe not so much about lumens as distribution. Are you trying to light the yard from a single point? Is it centrally-located? Apr 26, 2017 at 17:11
• @isherwood - yes, from a single point on the side of the house out towards the lawn so I know things won't be even. I think working out an average will have to do. Apr 26, 2017 at 17:14
• ummm.. a dark-adapted eye requires very little light to be able to see quite clearly at night. Be nice and don't light the place up to the point your neighbors get pissed. Apr 26, 2017 at 18:49
• Do you mind if I asked what you ended up with? I am currently having the same problem. Thanks. Apr 18, 2018 at 14:56