How to Measure Your Recessed Can Light Size (With Diagrams)

Quick Summary

Measuring your recessed can light size starts with the inside diameter of the housing, not the outside trim or drywall cutout. After removing the trim and bulb, use a measuring tape to check the opening inside the can, then match that measurement to a compatible LED retrofit light. Common recessed can sizes include 4 inch, 5 inch, and 6 inch housings, with 6 inch lights being the most common. Once you know the size, review lumen output, color temperature, dimmability, and energy efficiency so your new retrofit lights fit both the fixture and the room.

Retrofitting your existing fixtures with LED lights is more than a simple upgrade. It can improve your space, save energy, and help reduce your electricity bill. Before choosing new retrofit lights, it helps to know how to measure recessed can light size correctly, so the fixture fits securely. From brightening your living room to improving kitchen task lighting, the right size LED retrofit can create a better balance of style and function for your next DIY project.

How to Measure Your Current Housing Size

If the room you’re working on has existing recessed lights, you’ll need to start by measuring the housing size. This is an important first step, because your new retrofit lights must match the housing diameter for a secure fit. Here’s how you can do it:

1. Remove the Trim: Carefully remove the trim and the existing light bulb from your fixture.

2. Measure the Diameter: Using a measuring tape, measure the diameter of the opening inside the housing. The standard sizes are 4 inches, 5 inches, and 6 inches.

   

3. Record the Results: Note your measurements and reference them when selecting your new LED retrofits.

Standard Sizes for Recessed Can Lights

4 inch recessed lights

• Standard ceiling cut-out size: 4-3/8 inches

• Inside diameter of housing (without trim): Approximately 4 inches

• Typical uses: Accent, task, and general lighting

5 inch recessed lights

• Standard ceiling cut-out size: 5-5/8 inches

• Inside diameter of housing (without trim): Approximately 5 inches

• The least common of the three most common can light sizes

• Most LED Retrofit modules are "5/6-inch" compatible

6 inch recessed lights

• Standard ceiling cut-out size: 6-3/8 inches

• Inside diameter of housing (without trim): Approximately 6 inches

• The most common recessed light size

The Wrong Way to Measure Your Recessed Can Light Size

Important Note: Measuring the outside of the trim or the diameter of the cut-out opening in the drywall will result in an inaccurate (larger) measurement. To correctly measure your recessed can light size, measure the inside of the housing that fits in the hole.

Check Product Specifications

Not all LED lights are created equal. Beyond size and beam angle, comparing product specifications ensures you choose lights tailored to your functional and aesthetic needs. Here are the most critical specs to review:

1. Lumen Output:
   Higher lumens mean brighter light. Choose the right lumen level based on the room’s purpose—higher for task areas like kitchens and lower for relaxation zones like bedrooms.

2. Color Temperature:

• Warm white (2700K–3000K) creates a cozy, inviting atmosphere, perfect for living rooms and bedrooms.

• Neutral white (3500K–4000K) balances warmth and brightness, ideal for dining areas or offices.

• Daylight (5000K) delivers a crisp, energizing light for kitchens, bathrooms, or workspaces.

3. Dimmability:
   Dimmable lights allow you to adjust brightness levels, offering versatility for any mood or occasion.

4. Energy Efficiency:
   LED retrofit lights use less energy than traditional bulbs. Opt for models with lower wattage to save on utility costs without sacrificing performance.

Find the Right Fit After You Learn How to Measure Recessed Can Light Size

No matter what you’re dreaming up for your next DIY project, you can use these simple steps to find the perfect retrofit lights to get the job done. Taking the guesswork out of things will help save time, money, and energy so you can focus on enjoying the results of your hard work.

When it comes to high-quality, energy-efficient retrofit lights, NuWatt has you covered. With a wide range of options and unparalleled customer support, we’re here to help you light up your home beautifully and sustainably. Ready to get started? Explore our retrofit recessed lighting Collection today and find the perfect lights for your next project.

FAQs

How Do I Measure a Recessed Can Light?
Remove the trim and bulb, then measure the inside diameter of the recessed housing. Do not measure the outside trim.

What Are the Most Common Recessed Can Light Sizes?
Common sizes are 4 inch, 5 inch, and 6 inch. Many retrofit modules are made for 5 or 6 inch housings.

Can I Measure the Drywall Opening Instead?
No. Measuring the drywall cutout can give you a larger and inaccurate size. Measure the inside of the can housing.

What Size Recessed Light Is Most Common?
6 inch recessed lights are the most common in many homes. They are often used for general room lighting.

What Specs Should I Check Before Buying LED Retrofits?
Check size, lumen output, color temperature, dimmability, and wattage. These specs help match the light to the room’s purpose.