Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
Most people still shop for a light bulb the way their parents did: by the watts printed on the old bulb. Watts measure the electricity a bulb uses, not how bright it is, and an LED bulb uses far fewer watts than an incandescent bulb for the same amount of light. That mismatch is why a shopper who picks by watts alone often comes home with a bulb that is too dim, too bright, or the wrong shade of white. The federal Lighting Facts label on the side of nearly every light bulb box already answers the real questions: how bright the bulb is in lumens, what color the light looks like, how long the bulb should last, and roughly what it costs to run.
This page shows how to read that label and match it against the old bulb already in the fixture, so a shopper leaves the store with the right bulb the first time. It covers the label's brightness, color, cost and life figures, the base size that has to fit the fixture, and whether the fixture needs a bulb rated for a dimmer switch or an enclosed fixture. It does not cover the physical work of installing a bulb, wiring a fixture, or a smart or connected bulb's app features. If a marking is missing, damaged, or hard to read, the safest step is to ask the manufacturer or a lighting retailer rather than guess.
Necessary equipment
| Item | Note |
|---|---|
| Flashlight optional | A flashlight helps you read a marking in a dim fixture. |
| Pen and paper | Pen and paper let you record every marking you find. |
| Phone with a camera optional | A photograph is a backup record of a marking on a bulb or a box. |
| Step stool optional | A step stool lets you reach a fixture above your head. |
Prepare to compare bulbs
Estimated under a minute
- Find the fixture that needs a new bulb.<1mReport a problem with step 1, Prepare to compare bulbs
- Set the light switch to OFF.<1mReport a problem with step 2, Prepare to compare bulbs
Examine the old bulb and the fixture
Estimated 3 min to 4 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
SET THE LIGHT SWITCH TO OFF BEFORE YOU TOUCH THE BULB.
Electricity in the socket can shock you.
LET THE BULB BECOME COOL BEFORE YOU TOUCH IT.
A bulb that was on recently can burn your hand.
- Remove the old bulb from the socket.<1mReport a problem with step 1, Examine the old bulb and the fixture
- Find the base code on the old bulb, such as E26 or E12.<1mReport a problem with step 2, Examine the old bulb and the fixture
- The base code is often near the metal threads or the pins.
- Write the base code on paper.<1mReport a problem with step 3, Examine the old bulb and the fixture
- Find the wattage marking on the old bulb.<1mReport a problem with step 4, Examine the old bulb and the fixture
- Write the wattage on paper.<1mReport a problem with step 5, Examine the old bulb and the fixture
- Look at the fixture. Decide if it fully encloses the bulb.<1mReport a problem with step 6, Examine the old bulb and the fixture
- An enclosed fixture has a solid cover with little airflow around the bulb.
- Write your answer about the fixture on paper.<1mReport a problem with step 7, Examine the old bulb and the fixture
- Decide if the fixture connects to a dimmer switch.<1mReport a problem with step 8, Examine the old bulb and the fixture
- Write your answer about the dimmer switch on paper.<1mReport a problem with step 9, Examine the old bulb and the fixture
Read the Lighting Facts label on the new bulb
Estimated 4 min to 6 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Find a bulb box with the base code and the shape you need.1mReport a problem with step 1, Read the Lighting Facts label on the new bulb
- Find the Lighting Facts label on the side or the back of the box.<1mReport a problem with step 2, Read the Lighting Facts label on the new bulb
- Find the Brightness value in lumens on the label.<1mReport a problem with step 3, Read the Lighting Facts label on the new bulb
- Compare the lumens value with the wattage of your old bulb.<1mReport a problem with step 4, Read the Lighting Facts label on the new bulb
- A 40-watt bulb needs about 450 lumens or more.
- A 60-watt bulb needs about 800 lumens or more.
- A 75-watt bulb needs about 1,100 lumens or more.
- A 100-watt bulb needs about 1,600 lumens or more.
- A 150-watt bulb needs about 2,600 lumens or more.
- Find the Light Appearance value in kelvin on the label.<1mReport a problem with step 5, Read the Lighting Facts label on the new bulb
- The scale on the label runs from 2,600 K to 6,600 K.
- Match the kelvin value to the light color you want.<1mReport a problem with step 6, Read the Lighting Facts label on the new bulb
- A value near 2,700 K to 3,000 K gives a warm white light. This matches a standard bulb.
- A value near 3,500 K to 4,100 K gives a cool white light. This works well in a kitchen.
- A value near 5,000 K to 6,500 K gives a daylight color. This works well for reading.
- Find the Estimated Yearly Energy Cost and the Life value on the label.<1mReport a problem with step 7, Read the Lighting Facts label on the new bulb
- These two values let you compare the running cost of two different bulbs.
- Find a Contains Mercury statement on the label, if the bulb has one.<1mReport a problem with step 8, Read the Lighting Facts label on the new bulb
- The rule requires this statement only when the bulb contains mercury.
Compare the new bulb with the old bulb and the fixture
Estimated 1 min
- Compare the base code on the box with the base code you wrote down.<1mReport a problem with step 1, Compare the new bulb with the old bulb and the fixture
- If the fixture has a dimmer switch, find a DIMMABLE mark on the box.<1mReport a problem with step 2, Compare the new bulb with the old bulb and the fixture
- The DIMMABLE mark shows that the bulb works with a dimmer switch.
DO NOT INSTALL A BULB WITHOUT AN ENCLOSED FIXTURE MARK IN AN ENCLOSED FIXTURE.
Trapped heat can shorten the life of a bulb not rated for this use.
- If the fixture fully encloses the bulb, find an enclosed fixture mark on the box.<1mReport a problem with step 3, Compare the new bulb with the old bulb and the fixture
- This mark shows that the bulb can run inside an enclosed fixture.
Record your choice
Estimated under a minute to 1 min
- Take a photograph of the Lighting Facts label with a phone.<1mReport a problem with step 1, Record your choice
- A photograph keeps every marking together for the store.
- Keep your paper notes with the fixture information for the next purchase.<1mReport a problem with step 2, Record your choice
- Buy the bulb that matches your notes.<1mReport a problem with step 3, Record your choice
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- Lighting Facts label
- Also called: the label on the box, nutrition label for light bulbs, light bulb label, energy label for bulbs
- lumens
- Also called: brightness rating, how bright a bulb is, lumens vs watts
- watt equivalent
- Also called: 60 watt equivalent, 75 watt equivalent LED, old bulb wattage
- correlated color temperature
- Also called: warm white or cool white, color temperature, Kelvin rating, soft white vs daylight
- medium screw base (E26)
- Also called: E26 base, regular bulb base, standard screw base
- candelabra base (E12)
- Also called: E12 base, small base bulb, chandelier base
- dimmable LED bulb
- Also called: dimmable bulb, works with a dimmer switch, dimmer compatible bulb
- enclosed fixture rated
- Also called: enclosed fixture bulb, totally enclosed fixture, rated for enclosed fixtures
When to use a professional
Ask the bulb manufacturer or a lighting retailer about an unclear or an absent marking. Ask a licensed electrician about a fixture that shows damage or a burn mark. This page gives no instruction for the wiring of a fixture or a switch.
Common questions
What is a 60 watt equivalent LED bulb?
It is an LED bulb chosen to give roughly the same brightness as an old 60-watt incandescent bulb, not a bulb that draws 60 watts itself. ENERGY STAR's own purchasing chart lists 800 lumens as the minimum brightness that matches a 60-watt bulb, and the U.S. Department of Energy gives a real-world example of an 800-lumen LED using only about 6 to 10.5 watts to do it. The safest way to match brightness is to compare the lumens number on the new box's Lighting Facts label against that chart, not to trust the word 'equivalent' printed on the box alone, since equivalence claims are marketing language and are not standardized the way the Lighting Facts label is.
Lumens vs watts: how do I know how bright a bulb really is?
Lumens, printed on the Lighting Facts label as 'Brightness,' measure the light a bulb puts out. Watts, printed as 'Energy Used,' measure the electricity a bulb draws. An LED bulb can put out the same lumens as an old incandescent bulb while drawing a fraction of the watts, which is the whole point of the technology, so watts alone will not tell you how bright a new LED bulb is. Read the lumens number and ignore the watts number when you are judging brightness.
Warm white or cool white: which one should I buy?
It depends on the room, and the Light Appearance number in kelvin on the Lighting Facts label tells you which one you are holding. ENERGY STAR's purchasing materials describe a value near 2,700 K to 3,000 K as warm white or soft white, the standard color of an old incandescent bulb and a common choice for living areas and bedrooms. A value near 3,500 K to 4,100 K reads as cool white or neutral white, often chosen for kitchens and workspaces, and a value near 5,000 K to 6,500 K reads as daylight, often chosen where reading detail matters.
How do I know which LED bulb to buy for a specific fixture?
Start with the bulb already in the fixture, not with the new bulb on the shelf. Record its base code, its wattage, whether the fixture is on a dimmer switch, and whether the fixture fully encloses the bulb, then match each of those against the new box: the base code against the base of the new bulb, the wattage against the lumens chart, and the dimmer or enclosed-fixture need against the extra markings elsewhere on the box, since neither of those two is part of the federal Lighting Facts label itself.
What is the difference between an E26 base and an E12 base?
Both are ANSI standard screw bases named in the U.S. Department of Energy's own lighting purchasing guidance, and they are not interchangeable sizes. E26 is the medium screw base used on most standard household bulbs. E12 is the smaller candelabra base often found on chandeliers, sconces and decorative fixtures. A bulb with the wrong base will not fit the socket, so the safest way to confirm the size is to compare the new bulb's base directly against the old bulb rather than guess from the fixture's appearance.
Do I need a special LED bulb for a dimmer switch or an enclosed fixture?
Often, yes, and neither requirement appears on the federal Lighting Facts label itself, so you have to check the rest of the box. The U.S. Department of Energy advises checking the packaging to confirm a bulb can be dimmed if the fixture needs that. The Department of Energy also notes that a fully enclosed fixture traps heat, which can shorten the life of an LED bulb that is not rated for that use, so look for an enclosed-fixture mark on the box when the fixture fully encloses the bulb.
Related procedures
- How to change landscape light bulbs and work out if my transformer can take them
- How do I change the light bulb inside my oven?
- How to change a headlight bulb
- How to find and record the model and serial number of every appliance in the house
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 116 CFR 305.23 – Labeling for lighting products
- Tier 1The FTC "Lighting Facts" Label: Questions and Answers for Manufacturers
- Tier 1LED Bulbs Made Easy (Light Bulb Purchasing Guide)
- Tier 1How to Choose the Right ENERGY STAR Qualified Light Bulbs (Bulb Purchasing Guide checklist)
- Tier 1Purchasing Energy-Efficient Light Bulbs
Revision history
Current version 1 · updated 2026-08-03 · next review due 2027-08-03
- v1 · 2026-08-03First draft. Every figure on this page traces to a tier-1 source: 16 CFR 305.23 (eCFR, read directly) and the FTC's own Lighting Facts Q&A corroborate the exact list of fields the federal label must carry and its 2,600 K to 6,600 K Light Appearance scale; the ENERGY STAR Light Bulb Purchasing Guide and its companion checklist PDF (both energystar.gov, fetched directly after the equivalent HTML pages returned an automated-request block) supply the watt-to-lumens equivalence chart and the named color-temperature ranges; the DOE Federal Energy Management Program page supplies the ANSI base-type codes, the dimmable-packaging check, and the enclosed-fixture heat/life NOTICE. No specification on this page is safety-critical under config.json's list, and none is marked verified, because data/specs.json is out of scope for this session; the two fixture-specific values (base type, minimum lumens) publish as instructions to consult the old bulb or the chart on this page rather than as a guessed universal number. The backlog entry's premise that dimmability and enclosed-fixture rating appear on the federal label itself does not hold up against the regulation text (16 CFR 305.23(b)(3)(ix) bars any content beyond the enumerated list) and this record corrects that: those two facts are real and sourced, but they sit elsewhere on the box, not on the Lighting Facts panel. No competitor page was opened while drafting; the topic was screened before research per the phase 1 and exclusion lists in config.json.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.