Fluorescent tubes generally have a two-pin fitting at both ends of the tube and generally, length goes hand in hand with wattage – the longer the tube the higher the wattage.

T12 38mm (G13) Fluorescent Tubes

The largest size T12 (38mm) is no longer being manufactured, however, they did use the same G13 cap as the T8 fluorescent tube which means that you can replace the T12 tubes with the more efficient T8 of the same length. See T8 section below for suitable alternatives.

T8 26mm (G13) Fluorescent Tubes

Standard size T8 (26mm) tubes use the G13 fitting with 13mm between the two pins.

T5 15mm (G5) Fluorescent Tubes

The small T5 (16mm) tubes use the G5 fitting with 5mm between the two pins.

T4 12mm (G5) Fluorescent Tubes

The undercabinet T4 (12mm) tubes use the G5 fitting with 5mm between the two pins.

T2 7mm (W4.3) Fluorescent Tubes

The ultra-slim T2 (7mm) tubes use a fitting called a W4.3 with 4.3mm wide push-fit fitting.

Colour Temperature

Although most lamps emit white light, this can vary from a cosy warm white to a cold white according to the colour temperature of the lamp. The following chart shows the code numbers used for some of the most popular types:-

Colour TempColour CodeDesignationApplication
2700K827Very warm whiteSimilar light to incandescent light bulbs, giving a warm cosy feel
3000K830Warm whiteThe colour of most halogen lamps. Appears slightly whiter than ordinary incandescent lamps
3500K835WhiteThe standard colour for many fluorescent and compact fluorescent tubes
4000K840Cool whiteGives a more clinical or high tech feel
6000K860DaylightFluorescent or compact fluorescent lamps simulating natural daylight.
6500865Cool daylightExtremely white light used in specialist daylight lamps

Colour Temperature Codes (for illustration only, colours may not be exact)

You can read our guide to find out more about colour temperature.

Colour Rendering Definition

The Colour Rendering Index is an industry-standard reference to a light bulb on how well it renders colours of objects it is illuminating. Codes range from 0 to 100, the higher the number the more vivid and lively things look under that light. The lower the CRi rating the more ghostly (faded, dead) objects appear.

If you want your items and people to look good, then high CRi is required. High CRi light bulbs generally cost more to buy and cost more to operate as they have low lumen output per watt consumed. Low CRi light bulbs put out low-quality light, but are very cheap to operate as they have high lumen output per watt consumed.

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David Hebden

Need T2,15w,6400k bulb for bathroom cabinet


Hi, I’m looking for 1500mm by 26mm tube. The box from the old tube says 5200 Lumen and 68 KWh F58W/835
Which tube can I order from your site?

Last edited 1 month ago by Ingrid

I have an older big electronic bug killer that takes F25ft8/350BL bulbs that cost $35 a piece and are eighteen inches long. F15t8 bulbs are also 18 inches long and 8 to 10 bucks. Will this cheaper bulb work in its place?

Peter Hill

I have two different types of 4-foot tubes and I want to make sure I order the same but the letters and numbers do not match – I have L36W/23 and I have F40W/W-RS. Can you please advise what I need to order as replacements? Thank you – Peter


Hi can you help me please, looking to replace the following fluorescent tube bulbs, WL2001-6W ,8W and 24W T5 220-240V 50HZ G5,with possibly LED tube lights? What do you recommend? Thank you.

Jon Phillips

I have an Osram LUMILUX HO54W/840 which I want to replace. It is 116 cm long and has a diameter. Of 15 mm. Do you have it? jon_phillips@mail.com.

Steve Murphy

Hi guys … I am planning to make an exposure ‘light box’ for screen printing. I would like to use 5, Sylvania UV tubes (BL368). Friends now tell me that I may need ballasts … ? What do you say and how would it (they?) be wired to the lamps? Please advise … Cheers – Steve


I have fitted a new tube and started motor but the light is still flickering on and off. Any idea how I can fix this?


Is there an equivalent for the T2 640mm 15W 6400k

David Hebden

Hi Richard, I need same bulb for bathroom cabinet, did you manage to get one ?


F18W/35 – what is the bulb on your website that will match this fluorescent tube?

David Blakeslee

I have been looking for a replacement florescent tubes for our undercounter kitchen lighting. I have been searching at Home Depot, Ace, Lighting stores and on line for 3 months now and I cannot find the replacement tubes that I need. The replacement tubes need to be F10T5/cool white 10 watt. this tube is total length (including connecting prongs) is 50mm or 16 3/8 inches, Diameter is 5/8 inches. Can you tell me if these are still available and where I can find them. Thank you

David Blakeslee


Help please I need to replace a crompton 13w 835 A01 fluorescent tube tight measuring 65cm or 23 inches without pins. Thank you.


How do i replace an old starter for a 48inch tube?

Chris B.

I’d really like to send an email to someone to ask for advice but I can’t locate an email address. Basically I need to order 2 x F16W 135 T8 warm white. What product code?

Richard Latham

Im Trying to build a moveable wall of 8 ft x 6 ft with a florescent tube 1 ft apart the whole way down the wall is this possible with just the tube showing not the whole tin housing 


Dose the fluorescent tube size include the pins


Why don’t they put the color of the light on the tube. ? So I know what color to buy again.


Thanks for clearing up a query that was giving me a headache. Was trying to find a 4ft tube with a 38mm diameter which is apparently the old style tube and hard to find as discontinued. You can now use the newer T8 tube which is 26mm diameter but with the same end fittings. Many thanks.