What Are The Different Types of Light Bulbs? All Shapes & Sizes Explained

Choosing the right lighting is essential for both energy efficiency and functionality. There are many different light bulb types, each designed for specific uses, ranging from residential and commercial spaces to outdoor lighting and industrial applications. Some bulbs prioritize brightness, while others focus on longevity and energy savings. Knowing the various options well can help you select the best lighting for your needs.

Most common types of light bulbs and their key features

Each type of light bulb serves a specific purpose, offering distinct advantages for different settings. Whether you prioritize energy efficiency, brightness, or longevity, selecting the right bulb can make a significant difference.

1. LED (Light-emitting Diode)

LED bulbs are the most energy-efficient and long-lasting lighting option available today. Unlike traditional incandescent bulbs, LEDs do not rely on filaments to emit light. Instead, they use semiconductors to generate illumination, making them far more durable and efficient.

These bulbs consume significantly less electricity, produce minimal heat, and are available in various color temperatures, measured in Kelvin, for different lighting applications. There are various types of LED light bulbs, including MR16 bulbs, reflector bulbs, and PAR bulbs, making them suitable for task lighting, recessed lighting fixtures, pendant lights, and commercial settings.

Pros:

• Extremely energy-efficient, using up to 80% less electricity than incandescent bulbs
• Long lifespan, reducing replacement and repair costs
• Available in a variety of lighting options, including warm white, daylight, and cool white
• Compatible with a wide range of lighting fixtures, from pendants to track lighting
• Dimmable LED versions offer adjustable brightness for enhanced ambiance

Cons:

• Higher upfront cost compared to incandescent or halogen bulbs
• May require specific dimmer switches for full compatibility
• Color appearance can vary based on the manufacturer
• Some lower-quality LED options may flicker or degrade over time

Switching to LED bulbs is the best way to reduce electricity costs, improve lighting efficiency, and increase longevity.

Contact us today to learn more about custom LED solutions for your home or business.

2. Fluorescent 

Fluorescent bulbs are commonly used in commercial settings, offices, warehouses, and schools due to their high efficiency and longer lifespan compared to traditional incandescent bulbs. These bulbs work by exciting mercury vapor, which produces visible light when it reacts with a phosphor coating inside the tube.

Fluorescent bulbs, including fluorescent tubes and compact fluorescent lamps (CFLs), provide bright, even illumination, making them ideal for general lighting. However, they require ballasts for operation and can flicker over time. When considering LED vs fluorescent, LEDs offer a more energy-efficient and longer-lasting alternative, with lower maintenance costs and improved durability, making them a superior choice for modern lighting solutions.

For businesses or homeowners looking for information on how to convert fluorescent light to LED, several options exist, including ballast-bypass LED tubes, plug-and-play LED replacements, or full fixture replacements. Each method provides greater efficiency, lower energy consumption, and improved lighting performance while eliminating the need for ballasts and reducing long-term maintenance costs.

Pros:

• More energy-efficient than traditional incandescent bulbs
• Long lifespan, reducing maintenance and replacement costs
• Available in a variety of lighting intensities, measured in lumens, for different applications
• Commonly found in office lighting, warehouse lighting, and industrial spaces
• Suitable for overhead lighting and recessed lighting fixtures

Cons:

• Contains mercury, requiring careful disposal to avoid environmental hazards
• Can flicker or take time to reach full brightness
• Not ideal for accent lighting due to size and bulk
• Less efficient than modern LED alternatives
• May require an electrician for installation or ballast replacements

Consider switching to LED lighting solutions for better energy efficiency, longer lifespan, and improved brightness.

3. Halogen

Halogen bulbs are an improved version of traditional incandescent bulbs, using halogen gas to increase efficiency and extend lifespan. They emit a bright, white light and are often used for task lighting, pendant lights, and recessed lighting fixtures. These bulbs heat a tungsten filament, which allows them to maintain brightness longer than traditional incandescent options.

Pros:

• Brighter than incandescent bulbs with a concentrated beam of light
• Dimmable, making them versatile for different ambiance settings
• Affordable and commonly found in landscape lighting, gallery lighting, and overhead fixtures
• Better color rendering than CFLs and fluorescent lamps

Cons:

• Less efficient than LEDs, consuming much energy
• Shorter lifespan compared to LED bulbs
• Generates heat, which can increase cooling costs in indoor environments
• Fragile and requires careful installation

4. Incandescent Bulb

Incandescent bulbs are one of the most commonly used light bulb types, known for their warm glow and affordability. They work by passing electricity through a filament, causing it to heat up and emit a bright light. While inexpensive, these bulbs are less efficient and have a short lifespan compared to modern options.

When comparing the incandescent light bulb vs LED bulbs, LEDs consume significantly less energy, last much longer, and produce minimal heat, making them a more cost-effective and energy-efficient alternative. Upgrading to LEDs can reduce electricity costs and maintenance while providing better illumination.

Pros:

• Low cost and widely available
• Compatible with most lighting fixtures, including pendants, chandeliers, and recessed lighting fixtures
• Dimmable, allowing for customizable ambiance
• Variety of lighting colors, measured in Kelvin, to match different preferences

Cons:

• Very inefficient, wasting energy as heat
• Short lifespan, requiring frequent replacement and repair
• Consumes much energy, increasing electricity costs
• Not environmentally friendly, as they do not meet modern energy-efficient standards

5. Compact Fluorescent

Compact fluorescent bulbs (CFLs) are a more energy-efficient alternative to incandescent bulbs. They use a gas-filled tube and a small amount of mercury vapor to produce visible light when electrified. CFL bulbs last longer than incandescents and consume less energy, making them a popular choice for residential and office lighting.

Pros:

• More energy-efficient than incandescent bulbs
• Longer lifespan, reducing replacement frequency
• Available in various wattages and color temperatures
• Affordable and commonly used in household lighting

Cons:

• Contains mercury, requiring careful disposal
• Takes time to reach full brightness
• Not as long-lasting as LED bulbs
• Limited dimming capabilities

6. Fluorescent Lamps

Fluorescent lamps are commonly found in commercial and industrial spaces. They use mercury vapor and phosphor coatings to produce bright, even illumination, making them ideal for general lighting in offices, hospitals, and schools. While they last longer than incandescent bulbs, they require ballasts for operation.

Pros:

• More energy-efficient than incandescent bulbs
• Bright, even light output, making them ideal for commercial settings
• Available in various lengths and wattages
• Suitable for overhead and recessed lighting applications

Cons:

• Contains mercury, requiring proper disposal
• Not ideal for decorative or accent lighting
• May flicker or degrade over time
• Not as efficient as LED alternatives

 Contact us today to explore LED replacement options for commercial lighting solutions.

7. HID (High-Intensity Discharge) Bulbs

HID bulbs are commonly used in street lighting, stadiums, and large outdoor areas. These bulbs emit a bright, intense light using an electrical arc between electrodes. They are more efficient than incandescent bulbs but less efficient than LEDs.

Pros:

• Very bright, making them ideal for large spaces
• Longer lifespan than incandescent and halogen bulbs
• Used in high-output applications like stadiums and commercial parking lots

Cons:

• Requires a ballast for operation
• Can take time to reach full brightness
• Less efficient than LED alternatives

8. Type PAR Bulb

PAR (Parabolic Aluminized Reflector) bulbs are commonly used in track lighting, floodlights, and recessed lighting fixtures. They provide a concentrated beam of light, making them ideal for accent and task lighting.

Pros:

• Bright, focused illumination
• Energy-efficient when using LED versions
• Available in various sizes and beam angles

Cons:

• Halogen versions consume much energy
• Some types require specialized fixtures
• Non-LED versions have shorter lifespans

9. Smart Bulbs

Smart bulbs use Wi-Fi or Bluetooth connectivity to allow remote control via smartphone apps, voice assistants, or automation systems. They offer customizable lighting options, including adjustable brightness, color changes, and scheduling.

Pros:

• Can be controlled remotely through apps or voice assistants
• Customizable color temperature and brightness settings
• Energy-efficient, especially in LED versions
• Can integrate with smart home systems

Cons:

• Higher upfront cost compared to traditional bulbs
• Requires a compatible device or app for full functionality
• Some brands may have connectivity issues

10. Reflector Lamps

Reflector lamps are designed to direct light forward, producing a stronger and more focused beam. These bulbs are commonly used in floodlights, track lighting, and accent lighting applications.

Pros:

• Provides intense, directed illumination
• Available in multiple beam angles for different lighting needs
• Energy-efficient options available in LED versions

Cons:

• Non-LED versions consume much energy
• Can generate excessive heat in enclosed fixtures
• Some require specific housing for proper installation

11. Dimmable Bulbs

Dimmable bulbs allow users to adjust brightness levels to create different ambiance settings. Available in incandescent, halogen, CFL, and LED versions, these bulbs work with compatible dimmer switches for greater lighting control.

Pros:

• Adjustable brightness to suit different moods and settings
• Available in multiple light types, including LED for energy efficiency
• Helps reduce energy consumption when used at lower brightness levels

Cons:

• Requires a compatible dimmer switch
• Some CFL and LED dimmable bulbs may flicker if not used with proper dimmers
• Higher cost than non-dimmable alternatives

Find the perfect light bulb for your space—explore your options today!

All types of light bulb shapes and sizes

There are many styles of light bulbs, each identified by specific light bulb names and light bulb numbers. These classifications help determine a bulb’s shape, size, and intended use. The letters in the bulb’s designation refer to its shape, while the numbers indicate its diameter, typically measured in eighths of an inch.

Getting to know these categories helps in choosing the right bulb for different applications, whether for residential, commercial, or industrial use.

1. A Series

A-series bulbs are among homes and businesses' most commonly used light bulbs. The "A" stands for Arbitrary, referring to their classic rounded shape. These bulbs are widely used in table lamps, ceiling fixtures, and general-purpose lighting. They are available in various wattages and light outputs, with LED versions offering greater energy efficiency.

• A15 Light Bulb: A smaller version of the standard A19, the A15 is commonly used in appliance lighting, such as refrigerators and ceiling fans. It provides a focused but soft light, making it ideal for smaller fixtures.
• A19 Light Bulb: The standard bulb size for most household lighting, the A19 fits into most table lamps, ceiling fixtures, and sconces. It is available in incandescent, CFL, and LED versions, with LEDs being the most energy-efficient option.
• A21 Light Bulb: Slightly larger than the A19, the A21 produces higher light output and is used in larger fixtures or for brighter illumination. For LED lighting in the workplace, this is a great choice. 
• A23 Light Bulb: This is the largest in the A-series and is commonly used in high-lumen applications, such as commercial and industrial spaces where more light is needed.

2. B Series

B-series bulbs, or Blunt Tip bulbs, have a slightly pointed or flame-like shape. These bulbs are typically used in decorative lighting, such as chandeliers, wall sconces, and accent lighting.

• B8 Light Bulb: A small and narrow bulb, the B8 is commonly used in candelabra-style fixtures and holiday string lights.
• B10 Light Bulb: This size is ideal for wall sconces and chandeliers, offering a decorative touch while providing a warm, ambient glow.
• B13 Light Bulb: Often used in outdoor lanterns and ceiling fans, this slightly larger version offers enhanced brightness while maintaining a compact, decorative look.

3. C Series

C-series bulbs, or Conical bulbs, are similar to B-series bulbs but have a sharper tip. These bulbs are often found in holiday lights, decorative fixtures, and chandeliers.

• C7 Light Bulb: A small candelabra-style bulb, the C7 is commonly used in nightlights, Christmas lights, and accent fixtures.
• C9 Light Bulb: Slightly larger than the C7, this bulb is popular for outdoor string lights and marquee signage due to its vibrant glow.
• C11 Light Bulb: This size is frequently used in chandeliers and decorative sconces, providing a bright but elegant aesthetic.

4. G Series

G-series bulbs, or Globe bulbs, are recognized by their spherical shape and are often used in vanity lighting, pendant fixtures, and decorative displays.

• G16.5 Light Bulb: A small globe bulb that is commonly found in bathroom mirrors, pendant lighting, and decorative wall sconces.
• G25 Light Bulb: A medium-sized globe bulb often used in makeup mirrors and vanity lighting, offering a soft, even glow.
• G40 Light Bulb: The largest in the G-series, this bulb is used in statement lighting, high-end decor, and exposed bulb installations.

5. PAR Series

PAR (Parabolic Aluminized Reflector) bulbs are used in spotlights, floodlights, and recessed downlights. These bulbs provide a high-intensity, focused beam, making them suitable for task lighting and outdoor security lighting.

• PAR16 Light Bulb: A small spotlight bulb used in track lighting, accent lighting, and recessed downlights.
• PAR20 Light Bulb: Commonly used in residential and retail lighting, this bulb offers a narrow beam for targeted illumination.
• PAR30 Light Bulb: Ideal for outdoor floodlights, stage lighting, and high-ceiling fixtures, providing a wide, bright beam.
• PAR38 Light Bulb: A large floodlight used in security lighting, stadiums, and commercial spaces, offering high-intensity brightness.

6. R Series

R-series bulbs, or Reflector bulbs, are designed to direct light output forward, making them ideal for downlights, recessed lighting, and track lighting.

• R20 Light Bulb: A smaller reflector bulb used in residential ceiling fixtures and accent lighting.
• R30 Light Bulb: Frequently used in recessed ceiling fixtures, providing soft, diffused illumination.
• R40 Light Bulb: A larger version, perfect for commercial spaces, warehouses, and large indoor venues.

7. T Series

T-series bulbs, or Tubular bulbs, are often used in signage, industrial lighting, and specialty applications.

• T5 Light Bulb: A thin tube light used in display cases, under-cabinet lighting, and commercial signage.
• T8 Light Bulb: The most common fluorescent tube, found in office lighting, classrooms, and retail stores.
• T12 Light Bulb: An older fluorescent tube that is gradually being replaced by T8 LEDs by lighting retrofit companies.

8. ED Series

ED-series bulbs are used in high-intensity discharge (HID) lighting, often found in streetlights, parking lots, and stadiums.

• ED17 Light Bulb: A compact HID bulb used in security lighting and small commercial fixtures.
• ED28 Light Bulb: Commonly found in parking lot fixtures and streetlights, providing high-lumen output.
• ED37 Light Bulb: One of the largest HID bulbs, used in industrial lighting, large warehouses, and stadiums.

9. Specialty Bulbs

Some bulbs do not fit into standard classifications but serve unique purposes in various industries and applications.

• MR16 Light Bulb: A low-voltage reflector bulb commonly used in track lighting, display cases, and landscape lighting.
• Vintage Edison Bulb: A decorative bulb with exposed filaments, often used in restaurants, bars, and industrial-style fixtures.
• Smart Bulbs: Wi-Fi or Bluetooth-enabled bulbs that allow for remote control, dimming, and color customization.
• High-Pressure Sodium (HPS) Bulb: Found in streetlights and parking lot lighting, offering high-lumen output with an amber glow.
• Metal Halide Bulb: Used in stadiums and large industrial spaces, see our LED vs metal halide comparison chart for efficiency differences.

Light bulb size chart

Choosing the right bulb requires knowing the various sizes and applications available. This light bulb types chart helps identify bulb dimensions, including diameter (measured in eighths of an inch) and base type.

Different bulbs are designed for specific uses, from residential fixtures to various types of commercial lighting in offices, warehouses, and retail spaces.

If you’re unsure which bulb best suits your needs, consider taking a look at our foot candle calculator which can highlight how different bulbs impact efficiency and visibility in your space.

What type of light bulb should your business choose?

Selecting the right lighting for your business depends on energy efficiency, brightness, and application. LED bulbs provide the best longevity and savings, while fluorescent and HID options remain useful. The right choice balances lumens, wattage, and color temperature to optimize performance and comfort.

Our team will help assess your lighting needs and recommend the best solution, whether you’re upgrading to LED, or retrofitting an outdated system.

Contact us today to find the ideal lighting for your business.

Key takeaways on the different kinds of light bulbs

Learning more about the types of bulb options that are available helps in selecting the best lighting for your home or business.

• Bulbs are categorized by shape, size, and application, from A-series for general lighting to PAR bulbs for directional illumination.
• LEDs offer the best efficiency, lasting up to 25 times longer than incandescent options while reducing energy costs.
• Fluorescent and HID bulbs are still used in commercial and industrial settings but are gradually being replaced by LED solutions.
• Choosing the right bulb depends on factors like brightness, color temperature, and beam spread, all of which impact energy use and visibility.

If you’re ready to upgrade to better lighting, contact us for a consultation on the best options for your space.

FAQs

Are all light bulbs the same size?

No, light bulbs come in various sizes, measured in eighths of an inch based on diameter. Types include A19 incandescent bulbs, BR30 for recessed lighting, and MR16 for track lighting. Different lighting fixtures require specific bulb sizes for proper illumination, energy efficiency, and aesthetic appeal in indoor and outdoor spaces. 

How many types of light bulbs are there?

There are five main light bulb types: incandescent bulbs, CFL bulbs, halogen bulbs, LED bulbs, and fluorescent bulbs. Each varies in lifespan, energy efficiency, and light output. Incandescent bulbs emit a yellowish glow, while LEDs provide energy-efficient white light, making them ideal for general lighting, commercial settings, and specialty applications.

What is a standard light bulb size?

A standard light bulb size is typically an A19 incandescent bulb, measuring 2.375 inches in diameter. Other common sizes include BR30 for recessed lighting, R20 for accent lighting, and MR16 for spotlights. Light bulbs are selected based on wattage, measured in lumens, color temperature, and compatibility with various lighting fixtures.