Somewhere inside almost every light fixture in your house — printed on a small sticker near the socket, stamped into the metal, or molded into the plastic — is a phrase like MAX 60W. Most of us have seen it while changing a bulb and given it the same attention we give a mattress tag. That's a shame, because it's one of the few pieces of safety engineering in your home that speaks directly to you, and it's asking for exactly one thing: don't put a bigger bulb in here than I was built to handle. Understanding why that sticker exists — and how LED bulbs quietly changed the math around it — turns a routine bulb swap into an informed one.
The rating is about heat, not brightness
The wattage rating has nothing to do with how bright the fixture is allowed to be. Watts measure how much electrical power a bulb draws, and in a traditional bulb the overwhelming majority of that power becomes heat rather than light. So when a fixture says MAX 60W, it's really saying: this enclosure, this socket, and the wiring connected to it can safely shed the heat of a 60-watt bulb — and no more. The manufacturer tested the fixture with that load, measured how hot the socket and the wires above it got, and set the limit where everything stayed within safe temperatures. The rating belongs to the fixture as a physical object — how much air moves through it, how close the bulb sits to the socket, whether a globe traps the heat — which is why a bare-bulb ceiling fixture, an enclosed flush-mount dome, and a table lamp can all carry different numbers for the same size socket.
What overlamping actually does
Putting a bulb in a fixture that draws more watts than the rating allows is called overlamping, and its damage is slow, quiet, and cumulative. The extra heat doesn't cause a dramatic failure on day one; instead it bakes the fixture from the inside every hour the light is on. Socket contacts lose their spring tension and start making poor contact, which itself generates more heat. The insulation on the fixture's internal wires — often rated for specific temperatures — dries out, turns brittle, and eventually cracks, leaving conductors closer to exposed than anyone would like inside a closed ceiling fixture. Plastic sockets discolor and become crumbly; the sticker itself often browns. The genuinely unsettling part is that all of this happens out of sight, and the fixture keeps working normally while it degrades. Brittle insulation above a ceiling fixture is a fire risk sitting quietly in the one place nobody ever looks — which is precisely why the manufacturers put the limit in writing.
The LED twist: equivalent watts versus actual watts
Here's where modern bulb shopping gets interesting. LED packaging leads with a big friendly number like "100W equivalent," which describes the brightness — the light output of the old 100-watt incandescent bulb it replaces. The number that matters to the fixture is printed smaller: the actual wattage the LED draws, typically somewhere around 15 watts for a 100W-equivalent bulb. Since the fixture's rating is a heat budget and heat follows actual watts, a 100W-equivalent LED sits comfortably inside a MAX 60W fixture with room to spare. This is one of the rare cases where the modern option quietly dissolves an old constraint: fixtures that were stuck at modest brightness for decades because of their heat budget can now hold considerably brighter bulbs without going anywhere near the limit — no hardware changes, just physics working in your favor for once.
Reading the two numbers on an LED box
Because packaging leads with the equivalent number, it's worth knowing where the real one hides. The actual wattage usually appears on the front in small print — "15W = 100W" or similar — and always appears in the specification panel on the side or back, listed as wattage or energy used, alongside lumens and the estimated yearly energy cost. When you're checking a bulb against a fixture's rating, that actual-watts figure is the only number in the conversation. The comparison is delightfully simple: actual watts at or below the sticker, you're fine; above it, pick a different bulb. If the fixture's sticker has gone unreadable with age — they often do — the conservative habit is to treat it as a 60-watt fixture, which was the most common rating of the incandescent era, and to remember that nearly any LED you'd reasonably buy will land far below that anyway.
One wrinkle worth knowing about multi-bulb fixtures: on most chandeliers, vanity bars, and ceiling fan light kits, the rating printed near the sockets applies to each socket individually — MAX 60W on a five-arm chandelier means sixty watts per bulb, not a sixty-watt budget split five ways. Some fixtures spell it out ("60W MAX PER SOCKET"), some don't, and a few list a total for the whole fixture instead, so it's worth reading the exact wording rather than assuming. Either way, the same LED arithmetic applies at every socket: check the actual draw, not the equivalent number, and the math almost always works out generously in your favor.
Signs a fixture has been overlamped before
If you've just moved into a place, or you're changing a bulb in a fixture you've never opened, a ten-second look tells you a lot about its history. A browned or bubbled area on the fixture around the socket, a socket that looks toasted or feels crumbly, discolored or darkened glass near the top of a dome, wire insulation visibly cracked or flaking where it enters the socket, or that faint burnt-dust smell that persists after cleaning — these are the fingerprints of years of too-big bulbs. Sometimes you'll even find the culprit still installed: a 100-watt incandescent in a fixture plainly stickered for 60. Swapping in an appropriately sized LED stops the damage from progressing, but it doesn't repair what the heat already did to the socket and insulation, and that distinction matters.
The homeowner's entire role here fits in one sentence: read the sticker, read the actual watts on the bulb box, and keep the second number at or under the first. That's a five-second check that protects the parts of the fixture you can't see. Everything past that line — replacing a tired fixture, upgrading a socket, investigating heat damage — belongs to someone with a license, and the good news is that the check itself means you'll rarely need to make that call.