Crack Your Light Bulb Codes - Get The Right Type & Size LED

Working out how light bulbs are named and categorised can be a bit tricky at first.  But after reading this handy guide, you'll soon be decrypting labels like Tom Hanks in the DaVinci Code.

Every light bulb has a unique code associated with it. It's clearly printed on the base of the bulb and on the packaging. These codes are usually a combination of letters and numbers.  Over time, the more historically popular lighting types have become standard, and these are the ones that we've tried to cover here.

Once you get a hang of these, you'll no longer feel the need to bring the old globe into the shop to check it with the new one, and shopping online will be a breeze.

What the Letters Mean

The letters usually refer to the fitting type or another feature of the globe. For example:

E Edison Screw Base
The Edison screw base was developed by Thomas Edison himself.
The bulb has a threaded metal base which screws into a matching socket.
This became the standard in Northern America and continental Europe for general purpose lighting.
For example, you might have noticed that Ikea uses a lot of E14 'small edison screw' bulbs in their lamps and lighting fixtures.
B Bayonet Cap Base

The Bayonet cap has radial pins on the base of the light bulb that slip into L-shaped holes in the socket.  

It is traditionally the standard in Britain and colonial countries.

Historically it is similar to the fastening used for quickly attaching bayonets to rifles, hence the name.

Reflector Style Lamp

Reflectors are domes covered in reflective material that surround the light source in order to gather and reflect the light back into a more concentrated beam of light.

They often have a faceted surface, such as the “multi-faceted“ reflector used in MR16 haogens.

G Glass Type Lamp  This is a historical term that's still hanging around.
U U-Shaped 'U' shaped ceramic base mount found on GU10 lamps.
T Tube

e.g. Tubular fluorescent

What the Numbers Mean

The numbers generally refer to the distance between the electrical connectors or the width of the lamp.

Depending on the origins of the lamp, this measurement can either be in inches or millimetres.

Our LED replacements for common lighting types.

These are some of our LED replacements for common lighting types.

Putting It All Together

Put the letters and numbers together and things start to make a little more sense, now that you know what to look for. Listed below are a range of the most commonly used lamps that we now sell low energy LED replacements for:

  • MR16 - 'low voltage' down-lights (Multifaceted Reflector with 16 eighths of an inch front diameter)
  • GU10 - 'mains voltage' down-lights (originally Glass style with 10 mm between the pins)
  • B22 - regular style light bulb (Bayonet mount with 22 mm diameter)
  • E14 - candle style light bulb (Edison screw with 14 mm thread diameter)
  • T8 - office lighting tubes (Tubular fluorescent of 8 eighths of an inch diameter)
  • AR111 - retail store lighting (Aluminium Reflector with a 111mm front diameter)

Now you've got the product code down, the only thing left is choosing your colour temperature and beam angle. Oh wait, don't forget about energy efficiency and cost! Here's another blog post entitled "8 things to check when buying your next light bulb" that might shed some more light on the issue...

See our full range of quality LED bulbs and light fittings.

By |

Know someone who might be interested?
Share this article:

next post → ← older post

Got a Question?

stop sign

Please see our FAQ, delivery, pricing, and product pages for commonly asked questions and answers.

About Reduction Revolution

Reduction Revolution is a business focused on energy efficiency and sustainability. Our products will help slash your energy usage. But they also often improve comfort, save time, and reduce your maintenance costs. That's why we say waste less, live better.

Australia New Zealand Map

Reduction Revolution Pty Ltd is an Australian owned and operated business (ABN 74 141 672 764).

Since 2010 we have supplied over 40,000 customers across Australia & NZ.

Click the links below to find out more:

About Us
Blog Posts - Frequently Asked Questions - Delivery Details - Discounts & Wholesale - Warranty & Returns - Contact - Search

Meters & Monitors
Power Meters - Energy Monitors - Thermal Imaging - Thermometers - Water Monitor - Light Meter

LED Lighting
Downlights - Light Bulbs - Filament Bulbs - LED Tubes - Oyster Lights - Strip Lights - Batten Lights - Panels / Troffers - High Bays - Motion Sensors - Floodlights - Emergency Lights

Energy Savers
Heating & Cooling - Hot Water - Cooking - Standby & Control - Pool Pumps - Portable Power

Read Our Customer Reviews!

Latest Blog Posts

  • Should You Buy ALDI LED Light Bulbs? [2019 Review & Update]

    This weekend ALDI is selling a range of LED light bulbs under the name 'LIGHTWAY'. It seems they've done away with 'Muller Licht' brand from previous years (which got some terrible reviews). Although only on offer once a year, they're worth reviewing... read more

  • Top 10 Causes of (& Solutions to) High Energy Bills

    If you've received a high energy bill you can end up feeling pretty helpless. I've spoken to many people over the years who think their high energy bill was caused by: an electricity leak, a faulty appliance, an incorrect utility meter, or even... read more

  • Efergy Engage Hub Online Software Set-up (& Troubleshooting)

    This guide outlines some important steps in the set-up of the Engage Hub's online software. Step 1) Plug in, Power Up, & Register Connect the Hub to power and plug it into an ethernet port on your internet router. Place... read more