The Ultimate Guide to Light Bulb Types: A Global Reference

The Ultimate Guide to Light Bulb Types: A Global Reference

Ever stood in a store aisle or browsed online, completely baffled by the wall of light bulb options? You're not alone. The world of lighting is filled with codes like A19, E26, and B22 that can feel like a secret language. To make it more confusing, the standard bulb in the United States is different from the one in the United Kingdom or Europe.

This guide will demystify it all. As a leading LED manufacturer, we'll break down the different types of light bulbs by shape, base, and country, so you can choose the right bulb with confidence, no matter where you are.

Types by Shape: The Universal Language

First, let's talk about shape. The shape of a bulb is usually described by a letter followed by a number. The letter indicates the shape, and the number is the diameter at the widest point in eighths of an inch (in the US) or millimeters (globally).

• A-Series (Arbitrary): This is the classic, pear-like shape we all recognize. The A19 is the standard in North America, while its metric equivalent, the A60, is common worldwide.

• G-Series (Globe): These are perfectly round bulbs, often used in bathroom vanities and decorative fixtures.

• C-Series (Candle): Shaped like a candle flame, these are perfect for chandeliers and wall sconces.

• PAR & BR-Series (Reflector): These bulbs are designed to cast light in a specific direction, making them ideal for spotlights and track lighting.

The Biggest Difference: Bulb Bases by Country 

Here is where the most confusion happens. The base of the bulb, which connects to the light fixture, varies significantly by region. The two most common types are the Edison Screw and the Bayonet Cap.

Edison Screw (ES) - The Global Standard for Screwing In

This is the most common screw-in base, named after Thomas Edison. The number after the "E" indicates the diameter of the base in millimeters.

• E26 (Medium Base): This is the undisputed standard in the United States, Canada, and Japan. It has a 26 mm diameter base.

• E27 (Medium Base): This is the standard for all of Europe and many other countries worldwide. It has a 27 mm base.

Can you use an E26 bulb in an E27 socket?While they look almost identical and an E26 bulb can often physically screw into an E27 socket, it is not recommended. The slight difference in size and, more importantly, the difference in regional voltage (see below) can lead to poor performance, a shortened lifespan, or safety hazards. Always buy the correct bulb for your region.

Bayonet Cap (BC) - The Push-and-Twist Standard

Common in the Commonwealth countries, this base has two pins on the side that lock into the fixture with a simple push-and-twist motion.

• B22 / B22d: This is the standard light bulb base in the United Kingdom, Ireland, Australia, New Zealand, India, and parts of the Middle East and Africa.

Quick Reference Table: Bulb Bases by Country

A Final, Critical Check: Voltage!

Never forget voltage. Using a bulb designed for a lower voltage in a higher voltage socket is dangerous.

• 110-120V: Standard in North America and Japan.

• 220-240V: Standard in Europe, the UK, Australia, and most of the rest of the world.

Using a 120V American bulb in a 240V UK lamp will cause it to burn out instantly and can be a fire hazard.

Conclusion: Lighting Made Simple

Choosing the right light bulb doesn’t have to be complicated. By remembering to check three key things—shape, base (E26, E27, or B22), and voltage—you can find the perfect fit for any fixture, anywhere in the world.

Ready to find the right bulb? Our website automatically filters for your region to show you only compatible, high-quality LED options. Explore our full range of LED bulbs today!

Frequently Asked Questions (FAQ)

1. Can I use an E26 bulb in an E27 socket?While it may physically fit, we strongly advise against it due to differences in voltage and manufacturing tolerances that can pose a safety risk. Always match the bulb to your region's standard.

2. What is the standard light bulb in the UK?The most common standard light bulb in the UK uses a B22 Bayonet Cap (BC) base. However, the E27 screw base is also widely used, especially in fixtures imported from Europe.

3. Are A19 and E26 the same thing?No. A19 refers to the shape of the bulb (the classic pear shape), while E26 refers to the base of the bulb (the screw-in part). A standard bulb in the US is both A19 and E26.