Lumens measure how much light you are getting from a bulb. More lumens means it's a brighter light; fewer lumens means it's a dimmer light.
As per Energy.gov, the brightness, or lumen levels, of the lights in your home may vary widely, so here's a rule of thumb:
To replace a 100 watt (W) incandescent bulb, look for a bulb that gives you about 1600 lumens. If you want something dimmer, go for less lumens; if you prefer brighter light, look for more lumens.
Replace a 75W bulb with an energy-saving bulb that gives you about 1100 lumens.
Replace a 60W bulb with an energy-saving bulb that gives you about 800 lumens.
Replace a 40W bulb with an energy-saving bulb that gives you about 450 lumens.
You can also calculate lumens from watts and luminous efficacy, using the watts to lumens calculator at Rapidtables.com.
Light your home using the same amount of light for less money. By replacing your home's five most frequently used light fixtures or bulbs with models that have earned the ENERGY STAR, you can save $75 each year.
Learn about lighting choices to save you money at Energy.gov.