Fluorescent Bulb Sizes Chart

Fluorescent Bulb Sizes Chart

A current is passed through a tube filled with argon gas and mercury to power fluorescent bulbs. You’ll find that these bulbs have a long life span, ranging from 10,000 to 20,000 hours.

Fluorescent bulbs, when compared to other types of lighting, can be extremely energy efficient and produce relatively little heat.

Fluorescent bulbs are perfect for lighting vast areas, such as your basement, where minimal, minor work will be done. Fluorescents can now be used in almost any room in the house, thanks to new types of bulbs and fixture styles. Most fluorescent bulbs are incompatible with dimmers and require a ballast component to deliver the proper voltage.

Fluorescent Bulb Sizes Chart

A tube with two pins on either end is the most common type of fluorescent lamp. The tube’s diameter is measured in eighths of an inch, just like incandescent lamps. (Read Light Bulb Sizes Chart)

In our guide, you will see the parts of a fluorescent light bulb, the fluorescent tube lengths and the fluorescent light sizes, and how easy it can be to install fluorescent lights.

By the end, you’ll know which commercial product meets your needs and why they are better than incandescent bulbs.

What are Standard Fluorescent Bulb Sizes?

When you search for fluorescent lamps, you’ll find a few types on offer more than others. Here are the most common light bulbs you can find.

T5 Fluorescent Tubes

T5 fluorescent tubes are used to light retail stores, schools, office buildings, workspaces, and more because of their illuminating characteristics. They are cost-effective thanks to low energy consumption and the 30,000 hours lifespan.

The glass inside the glass of T5 tubes is also coated with an environmentally friendly phosphor coating to help prevent phosphors from accumulating mercury. The larger tubes were designed using multiples of the 11.8 inch and not the imperial foot. These fluorescent tubes’ electronic ballasts prevent overloading and incorporate features like quick start and easy installation.

Printable Fluorescent

Bulb Sizes Charts

Download the printable version of

all Fluorescent Bulb Sizes Charts

in our handy Cheat Sheet for Free


Tube BenefitsUsage Areas
Philips Lighting Fluorescent TubesLife expectancy of around 20,000 hours
Shatter-resistant models available
Schools, offices, factories, and retail areas
Sylvania Fluorescent TubesEnergy-efficient models
Enhanced color rendering performance
Used for all-around applications
Osram Fluorescent Tube lightReliable company backupUsed for domestic and commercial lighting
GE Fluorescent Tube lightsExcellent colour temperature
Extended lifespan and low mercury outputs
Domestic use, signage, industrial applications
GlassGuard Fluorescent Tube lightsIndustry approved shatterproof linear fluorescent tubes Retail, food industries, and more
RS Pro Fluorescent Tube lightsWaterproof units
Impact resistant lights
Manufacturing, food industries, and marine environments

How many ballasts per light fixture will be based on the number of parts of fluorescent lamp uses.

T8 Fluorescent Tubes

Because of the high levels of light generated, these fluorescent tubes are used for a wide range of home and commercial applications.

These tubes offer great color rendering index capabilities and are very energy efficient. T8 fluorescent tubes emit light such as cool white or warm white, proven to help prevent and treat the seasonal affective disorder (SAD). (Read 1 1/16 Socket Chart)

T12 Fluorescent Tubes

In 2012, the production of T12 fluorescent tubes ended. The tubes measure 1.49 inches with distinct kilowatt-hour wattages compared to other fluorescent tubes. You can replace T12 fluorescent tubes with T8 LEDs as they are similar in light generation with reduced energy use.

Circular Fluorescent Tubes

Circular Fluorescent Tubes

Available in T5, T6, and T9 formats, circular fluorescent tubes are often used by lighting designers for the illumination of well-lit interior spaces.

The fluorescent tubes deliver lots of energy efficiency with a slim design. Round fluorescent lamps will only be compatible with a current circular fluorescent tube fixture.

Fluorescent tubes and lamps come in many shapes and sizes, and thus the compact fluorescent lamp continues to gain popularity. It is often found that auxiliary electronics are integrated into the base of a lamp, thus allowing compatibility with a common light bulb socket.

Installation of CFL bulbs can cause significant savings for two reasons. Low running costs and a long lifespan. You also find they provide higher levels of illumination than typical incandescent light bulbs.

How Do I Know if My Ballast is T8 or T12?

Fluorescent lamps or fluorescent tubes are often T8 and T12. Magnetic ballasts were first used with T12 lamps, yet can be used with electronic ballasts, lighter than traditional ballasts, and produce less noticeable light flicker. Electronic ballasts designed specifically for T8 lamps are used in all of them. The choice between T8 and T12 lamps is based on your intended purpose or application. (Find the Best Battery Operated Lights)

If your tube lights no longer work, check the burned-out lamp’s writing. You will see at the end close to the prongs, fluorescent lamp identification will say in print T8 or T12. The same area will say the linear fluorescent tubes rated power, often 32 watts for T8 lamps and 40 watts for T12 lamps.

If you want to decrease light flicker and the hum you often hear, remove your existing T12 magnetic ballast, and you should be able to install a lighter-weight T12 electronic ballast.

You can then install T12 tubes in place, and based on your lighting preferences, choose between warm white and cold white according to the light output and color temperature you need from your CFL bulbs.

If you have concerns about heat, you will find T8 linear tubes are preferable over T12 tube lights as they give off less heat.

What is the Difference Between T8 and T12 Fluorescent Light Bulbs?

This is a question often asked is the difference between these bulbs. On the most basic level, the T12 and the T8 bulbs have different diameter tubes where the T12 is 1.5 inches in diameter, and the T8 is 1 inch in diameter.

The research found they could make the light tube thinner using the same technology yet increased energy efficiency.

T12 and T8 lamps also differ from the control gear of the ballast that they operate on most of the time. T12 uses magnetic ballasts as their control gear, and T8 bulbs use electronic ballasts.

The light sources socket is the same for both; you cannot use them with the same ballast. If you attempt to fit a T12 lamp in an electronic ballast, it flickers more and can have problems even if it lights up.

Commercial buildings or individuals who use them at home tend to use the instant start ballast to operate a T8 light bulb.

If you need to upgrade, you need to ensure you change the ballast. Besides this, most individuals prefer the color temperatures against the color rendering index with a T8 tube rather than the color temperature from a T12.

Color temperature is as much of a user choice as the energy efficiency, as this will impact the feel of your environment. (Find the Best Flashlight)

While T8 fluorescent tubes are used to save energy over earlier light source types of fluorescent tubes, the effect is essentially the same as any other linear fluorescent.

You have a phosphor-coated tube, which, when turned on, stimulates the phosphors, resulting in visible light and strength of lumen output. Besides the high output, you have tubes the same length; they use the medium bi-pin double contact, you can be hard pushed to tell the difference between the two fluorescent light bulbs.

When they found the narrowing of the tube’s diameter, the light bulb’s efficiency compared to other bulbs ramped up.

The compact fluorescent showed itself and led to a new generation of fluorescent lighting, which we still use, rather than turning to incandescent bulbs.

Now, we can find LED tubes are replacing T8 tubes. LED tube lights will fit the same correct size lamp socket as your older T8 and T12 bulbs.

Doing this makes them a self-explanatory retrofit option that delivers a speedy payback time. You can find these in use and for commercial purposes, while also there has been an improvement in color temperature.

Colors can be found and based on more than phrases such as cool white or natural daylight, but on the 4000K or 5000K, or other ratings you find. You can also use this to determine if your lamp is more modern as the T8 bulbs offer a much better color rendition where, in the older light bulbs and lamps, the color output of a fluorescent lamp wasn’t as important.

At the time, it was more about delivering the cheapest lamps to flood a market with fluorescent lighting options. It was once the marketplace continued to grow that people sought better color options in their lighting.

T12 bulbs are the earliest incarnation and were released before halogen lights made an appearance. The T12 light bulbs were introduced in the 40s and a considerable improvement. It was some 40 years later, in the mid-80s, when T8 lamp technology took off and soon set the trend as the new standard of energy efficiency, and prompting people to switch to these new types of lighting.

It took a while for T8 lighting to catch on since it required more than just changing a light bulb; it also required changing a ballast. Because the fluorescent light components were so old, some people had to change them entirely. The cost of switching to offer more energy-savings T8 tube lights was often the halting move. (Find the Best Solar Path Lights)

With the launch of LED T8 bulbs, people may now move to something even more energy-efficient, and they won’t require a ballast if they don’t want one. Thanks to a series of incentives, there has never been a better time to consider moving to something more energy-efficient.

The good news is that T8 light fixture sockets can be used with LED T8s, which are being added to the market all the time. A simple refurbishing of a decades-old fixture, as a type, can still be a viable lighting type now and in the future.

T12 fluorescent bulbs

What does T12 mean in fluorescent bulbs?

A T12 lamp twelve-eighths of an inch, or one-and-one-half inches in diameter. A T8 lamp is eight-eighths of an inch or one inch. And a T5 lamp will be 5/8ths of an inch.
The common tube ratings for general lighting are shown below.

You’ll find more, but the list is lengthy and ineffective for regular users. The Nominal Length may not perfectly match any of the tube’s measured dimensions.

For some tube sizes, the nominal length (in feet) is the required space between centers of lighting fixtures to produce a continuous line; therefore, the tubes are slightly shorter than the nominal length.

Our fluorescent light bulb sizes chart shows the common fluorescent light lengths and the common fluorescent tubes sizes. It doesn’t include any lamps with single pin bases as these are not common in a home scenario.

Printable Fluorescent

Bulb Sizes Charts

Download the printable version of

all Fluorescent Bulb Sizes Charts

in our handy Cheat Sheet for Free


Tube diameter measured in 1⁄8 inch incrementsNominal lengthNominal power (W)
T56 in (152 mm)4
T59 in (229 mm)6
T512 in (305 mm)8
T521 in (533 mm)13
T814 in (356 mm)14,15
T82 ft (610 mm)18
T83 ft (914 mm)30
T84 ft (1,219 mm)36
T85 ft (1,524 mm)58
T86 ft (1,829 mm)70
T1214–14.5 in (356–368 mm)14,15
T1216.5 in (419 mm)15
T122 ft (610 mm)20
T124 ft (1,219 mm)40
T125 ft (1,524 mm)65, 80
T126 ft (1,829 mm)75, 85
T128 ft (2,438 mm)125

When you want to know how to install a fluorescent light fixture, you can find it is straightforward and hasn’t changed too much from the early days you would install a fluorescent light fixture. How to install fluorescent lights will have more concern with how to install a fluorescent tube.

All you need to do is ensure the grooves align with the unit itself and slide the pins on either end into the grooves. Once in position, you can twist the tube until it locks in position.

Fluorescent Bulb Sizes Chart

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