Shopping for a replacement bulb used to be easy: you bought the same watts as the old one. Then LED bulbs arrived, and the old rule broke. A 60-watt incandescent bulb and a 9-watt LED can give the same light, so buying by watts now means buying the wrong brightness. The number that matters today is lumens, which measures how much light a bulb actually gives. This finder converts lumens into the wattage of each bulb type, so you can buy the right replacement with confidence.
The conversion uses average efficacy, which is lumens per watt. An old incandescent bulb gives about 14 lumens per watt, a halogen about 18, a CFL about 60, and an LED about 90. That is why an LED is so much cheaper to run: it turns far more of its power into light and far less into heat. To convert, you divide lumens by the efficacy. A bulb giving 800 lumens needs about 57 watts as incandescent, 44 as halogen, 13 as CFL, and under 9 as LED.
Here is a worked example. Your old bulb box says 800 lumens, which is the classic brightness of a 60-watt incandescent. Enter 800 and the tool returns about 57 watts incandescent, 44 watts halogen, 13 watts CFL, and 8.9 watts LED. In a shop, you would look for an LED marked 8 to 10 watts, or one labelled as a 60-watt equivalent, which is the same thing in plain language. The LED gives the same light for roughly one seventh of the power, which is where the savings come from.
Brightness needs differ by room, and lumens help you choose well. A small bedroom or hallway is comfortable at 400 to 800 lumens per bulb, while a kitchen or a workspace needs 800 to 1,100 or more, because you do detailed work there. A single dim bulb in a kitchen makes cooking harder and less safe, while a very bright bulb in a bedroom feels harsh at night. If a room feels wrong after a swap, the cause is usually lumens, not the bulb type, so check the number on the box first.
Two details catch buyers out after the wattage is right. The first is the fitting: a screw fitting and a bayonet fitting look similar in a photo but are not interchangeable, so check the old bulb base before ordering. The second is colour temperature, measured in kelvin: warm white around 2700K feels cosy and suits living rooms and bedrooms, while cool white around 4000K feels brighter and suits kitchens and bathrooms. The same lumens in the wrong colour can make a room feel completely different.
Old wattage labels still appear on LED boxes as equivalents, and they are useful once you understand them. A box saying 60-watt equivalent means the LED gives about 800 lumens, like the old 60-watt bulb, even though it uses only 9 watts. That label exists because shoppers still think in old watts, and it is honest as long as the lumens match. If a box claims an equivalent but lists very different lumens, trust the lumens, because they are the measured light output.
Use this finder whenever a bulb blows, and keep a note of the lumens that work in each room. When you replace the whole house over time, matching lumens room by room keeps the light feeling right, and the LED wattage tells you the running cost. Brightness is lumens, power is watts, and the two stopped meaning the same thing years ago. Once you shop by lumens, you will never buy a bulb that is too dim or too harsh again.