A compact fluorescent lamp (CFL), also known as a compact fluorescent light bulb, is a type of fluorescent lamp. Many CFLs are designed to replace an incandescent lamp and can fit in the existing light fixtures formerly used for incandescent's.

Compared to general service incandescent lamps giving the same amount of visible light, Compact Fluorescent bulbs use less power and have a longer rated life, but generally have a higher purchase price. In the United States, a CFL can save over $30 in electricity costs over the lamp's lifetime compared to an incandescent lamp and save 2000 times its own weight in greenhouse gases.

While the purchase price of a Compact Fluorescent bulb is typically 3 to 10 times greater than that of an equivalent incandescent lamp, the extended lifetime (fewer lamps to replace and reduced labor) and lower energy use will compensate for the higher initial cost in many applications. A US article stated "A household that invested $90 in changing 30 fixtures to CFLs would save $440 to $1,500 over the five-year life of the bulbs