Fluorescent Tubes - Get The Right Tube Every Time - Lightbulbs Direct

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 Temp	Colour Code	Designation	Application
2700K	827	Very warm white	Similar light to incandescent light bulbs, giving a warm cosy feel
3000K	830	Warm white	The colour of most halogen lamps. Appears slightly whiter than ordinary incandescent lamps
3500K	835	White	The standard colour for many fluorescent and compact fluorescent tubes
4000K	840	Cool white	Gives a more clinical or high tech feel
6000K	860	Daylight	Fluorescent or compact fluorescent lamps simulating natural daylight.
6500	865	Cool daylight	Extremely 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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Hi, looking for a T2-15W, 640 OK flourscent bathroom, above sink cabinet side light.

Does anyone know where I can get it.

0 Reply Stewart Smith June 18, 2024 3:17 pm

Hello. I have two double-tube light fittings linked in series. They don’t appear to have starters. Both tubes in one fitting (5ft, 58W) no longer work. Can I replace with equivalent LED tubes or will I need new fittings? Many thanks.

0 Reply Mat @ Lightbulbs Direct Author Reply to Stewart Smith July 12, 2024 10:30 am

Not all fluorescent fittings have starters. There are fittings that use a high frequency electronic ballasts to power/start the tube, however these are not compatible with LED tubes. To use LED tubes in these fittings, you would need to ‘bypass’ the ballast. The LED tubes include a wiring digram for how to do this in series, but we would recommend this woerk is carried out by a qualified electrician.

0 Reply Lorraine May 25, 2024 10:40 am

The T4 tube comes with plastic sleeves on either end. It is the right length Pin to Pin, but will only fit if I remove the plastic. Is this safe to do?

0 Reply Mat @ Lightbulbs Direct Author Reply to Lorraine June 7, 2024 10:43 am

I feel that the plastic sleeve may be an integral part of the tube and is unsafe to remove.

0 Reply Wayne May 20, 2024 8:29 pm

Hello, I’m trying to replace the fluorescent tube light in the kitchen as it flickers when switched on. Can you advise which tube I might need? The markings on the cradle/ tube holder are 70W T26.

Many thanks, W

0 Reply Wayne May 18, 2024 10:33 pm

Hi there, The kitchen tube light no longer works. When we switch on the light, the tube just flickers and struggles interminably. The only marking I could find is T26 70w. Can you advise on which replacement tube I need? Will I also need a starter?

Thanks,

0 Reply Mat @ Lightbulbs Direct Author Reply to Wayne May 23, 2024 11:22 am

Hi Wayne, a T26 tube is another term for a T8 tube – T26 = 26mm diameter, T8 = 8 eigths of an inch diameter (i.e. 26mm) – so you need a 6ft 70W T8 tube of which we sell in either White, Cool White or Daylight colour. As your current tube is struggling to start, you should replace the starter at the same time with this 70W-125W starter.

0 Reply Marie May 18, 2024 12:25 pm

What does H5 mean in a bulb.

0 Reply Mat @ Lightbulbs Direct Author Reply to Marie May 23, 2024 11:24 am

Could you be referring to a fluorescent T5 tube?

0 Reply Lesley April 7, 2024 4:16 pm

Are the T8 fluorescent tubes u supply suitable for an aquarium?

0 Reply Janine Taylor March 19, 2024 9:45 am

Hi there. I have a salon light up shelving unit that a couple of tubes need replacing. The tubes that were removed read ‘CROMPTON LAMPS BD4 8QE UK 13W WHITE E12’ but I can’t seem to find an E12. I would greatly appreciate your help in replacing said bulbs.

Thank you

0 Reply Mat @ Lightbulbs Direct Author Reply to Janine Taylor March 28, 2024 12:26 pm

Hi Janine, the E12 is a code which represents the date of manufacture of the tube – however as you’ve mentioned it is 13W and white – the tube you are after is this Crompton Lamps Fluorescent 21″ T5 Tube 13W Halophosphate White.

0 Reply Malcolm Davenport March 6, 2024 7:24 pm

I am trying to replace a 4 ft T8 Tube, 36w Triphoshor white F36W/835 fluorescent light bulb without success. I am struggling to find any. I just need one or two of them. Any ideas.

0 Reply Mat @ Lightbulbs Direct Author Reply to Malcolm Davenport March 7, 2024 2:21 pm

No problem, we stock them right here – 4ft T8 Tube 36W F36W/835

0 Reply Brenda Wilson February 29, 2024 11:10 am

Good morning l am looking for 3 foot flourescent tubes and starter. I have read that these particular tubes are no longer available but wondered if you had any stock as l don’t want to change the whole fittings. They are under counter lamps on to my work top . Hope you can advise. Many thanks

0 Reply Mat @ Lightbulbs Direct Author Reply to Brenda Wilson March 4, 2024 10:40 am

We still have stock of fluorescent 3-foot tubes, but we also stock 3-foot LED replacements. You have read correctly that they are now banned from import/manufacture but retailers are allowed to sell through any remaining stock they already have in the country.

0 Reply Mohammed Idris February 28, 2024 12:18 pm

Hello. My name is Mohammed. I wanted to ask I have one of your light tubes for the kitchen which has stopped working. The model is a 36w 865 E09. I just wanted to know is that a four foot tube or is it less? And when it stops working is it normally the starter motor is it the tube that normally stops? Thank You.

0 Reply Mat @ Lightbulbs Direct Author Reply to Mohammed Idris March 4, 2024 10:36 am

Hi, a 36W tube is normally a 4-foot tube. The length is very closely related to the wattage, so unless this is a very specialaty tube, we can be confident it is a 4-foot T8 tube. I suspect the tube will be the faulty component, but we always recommend you get a new starter when replacing a tube, as it will allow the tube to run more efficiently.

0 Reply Marina January 21, 2024 9:21 pm

Hi, do you sell a tube which is 1760mm? Not sure if I need to measure the pin length too which would maybe take it to 1800mm? Thank you.

0 Reply Mat @ Lightbulbs Direct Author Reply to Marina January 22, 2024 12:29 pm

Hi Marina, 6ft tubes are 1763mm without the pins – 1775mm with the pins, are you sure on the 1800mm measurement? That would make the pins 2cm in length – which seems overlay excessive.

0 Reply Brian Standfield January 12, 2024 9:23 am

My last note to you should have said realised that the tube i ordered was the wrong length

0 Reply Brian Standfield January 12, 2024 9:16 am

I have a light fitting with a lampT4 20W 520 between pins. would you have one in stock, I ordered one last night through you but now resized it is 580 in length

0 Reply Mat @ Lightbulbs Direct Author Reply to Brian Standfield January 17, 2024 10:10 am

Hi Brian, please contact our customer service team to help with this order/product – email: enquiries@Lightbulbs Direct.com or tel: 01494 723 286

0 Reply Dave January 10, 2024 10:11 pm

Hi, I have a bathroom mirror cabinet with T2 18w 6400k bulbs. I can’t seem to find the exact replacement. Also, if I were to go with a lower W, say 11W and 6000k, will this still work ok?

Do I need to consider the fitting type or are all T2 bulbs the same?

Any help would be great, thanks

0 Reply Mat @ Lightbulbs Direct Author Reply to Dave January 17, 2024 10:45 am

HI Dave, no you cannot use a different Wattage tube, there are electronic components in the fitting which will be designed to run a 18W tube specifically and will not work on a 11W. You can change the colour temperature though to any temperature such as your mentioned 6000K, this causes no issue at all. T2 tubes are very uncommon, and I cannot seem to find a reseller. Maybe you could try the manufacturer of the mirror cabinet?

0 Reply Dave Reply to Mat @ Lightbulbs Direct January 19, 2024 8:12 pm

Thank you, unfortunately I don’t know who the manufacturer is, I guess it’s put up without lights or change the cabinet. I’m unable to find a supplier

0 Reply Fiona Aylett January 5, 2024 3:54 pm

I am looking for a T2 15w 6400 with a push-fit fitting for a bathroom cabinet, . Can you help

0 Reply Mat @ Lightbulbs Direct Author Reply to Fiona Aylett January 17, 2024 10:46 am

Sorry Fiona, we do not have any T2 tubes. Maybe you could try the manufacturer of the cabinet?

0 Reply Winnard December 30, 2023 2:13 pm

Hi. I have a strip light bulb which states 36w/23. I am looking for a replacement but can only see 36w/865. What is the difference? Can I use 865 as a like for like replacement? What do yhe numbers after the slash mean?

Thanks

0 Reply Mat @ Lightbulbs Direct Author Reply to Winnard January 17, 2024 10:47 am

They refer to the colour of light the tube produces, 23 would be 2300K warm white, 865 is 6500K daylight (blue) coloured. As long as the replacement tube is 36W, you can use any colour

0 Reply Micheál November 13, 2023 2:17 pm

Hi, is there an alternative for an f58w/33-640. I know they’re being discontinued and want a straightforward swap

0 Reply Mat @ Lightbulbs Direct Author Reply to Micheál November 30, 2023 10:11 am

Hi Micheál – you can upgrade to LED T8 tubes with no fuss – our range of LED tubes come with a special LED starter that makes them compatible with the most popular type; magentic ballast fluorescent fittings. However, if you fitting is of the electronic ballast type, and therefore doesn’t have a starter, then you will have to get an electrician to re-wire your fittings to bypass the ballast. The LED tube you would require that directly replaces a F58W640 is our Crompton Lamps LED 5ft T8 Tube 24W Cool White.

0 Reply Crissy October 7, 2023 12:27 pm

Hi I want to buy a 1 foot 12 inches fluorescent 2 pin 15w bulb for my old Panasonic light it has the 2 end connectors for the tube to go into but not sure which tube bulb to buy and if any wattage is ok to use? any advise guys!

0 Reply Mat @ Lightbulbs Direct Author Reply to Crissy October 9, 2023 4:12 pm

Can’t quite identify this tube, can you measure the tube from pins to pins in mm please. Also is it as thick as say a finger, or much thicker?

0 Reply Rebecca Sweterlitsch September 22, 2023 8:04 pm

I have an excellent light box (Porta-Trace) that is a few years old. The bulb is Hitachi 15 watt F15T8/EX-N Hi-Lumic N Tri Phosphor Made in Japan. 18 inches. I’m using the light box currently to digitize old slides and have begun to see 2 yellow bands show up through my camera and on the resulting photo. I thought I’d try a new bulb. I can’t find one, even on eBay, with that exact description. I don’t mind a different brand, but I don’t know how to decipher that it will be the same output. Can you help? Thank you.

0 Reply Mat @ Lightbulbs Direct Author Reply to Rebecca Sweterlitsch October 5, 2023 11:16 am

You could try a Crompton branded 15W 18″ Triphosphor tube – All tubes tend to be manufactured to the same specifications so they can be interchanged, i.e. a 15W tube of one brand is the same light output of a 15W from another brand. You haven’t mentioned which colour your tube was, but for your purpose I suggest you purchase a daylight (865) one, as this will provide the best colour rendering for your digitizing project. If you find the digitized image is too ‘cool’ you can either adjust the colour-balance in a photo editing software, or if you can identify the colour of your old tube, we also sell them in White (835), or Cool White (840). To identify, look the the numbers 835, 840 or 865. For info, these numbers describe the colour output, the first number, 8, is for CRi 80, the last 2 digits for the colour in Kelvin, eg, 3500K, 4000K and 6500K.

0 Reply David Hebden August 11, 2023 11:22 am

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

0 Reply Ingrid July 31, 2023 2:16 pm

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 year ago by Ingrid 0 Reply Mike June 15, 2023 10:24 am

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?

0 Reply Mat @ Lightbulbs Direct Author Reply to Mike July 10, 2023 10:39 am

Although it will fit and work, the UV light output will be less, so it may not be as effective in attracting those bugs.

0 Reply Peter Hill May 31, 2023 2:56 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Peter Hill May 31, 2023 5:00 pm

From my research, the L36W/23 is a T8 tube, and the F40W/W-RS is a T12 tube – to confirm, can you see if the tubes are the same thickness? The T12 should have a wider diameter. Then, is there any indication on the fitting which type of tube should be used T8 or T12, or an indicated wattage 36W or 40W? T8 tubes are far, far more wide spread in use than T12 tubes, so I would suspect you require a 36W 4ft T8 tube of which you can choose from a selection of light colours, Warm White, White, Cool White or Daylight.

0 Reply Tracy May 27, 2023 10:24 am

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.

0 Reply Mat @ Lightbulbs Direct Author Reply to Tracy May 31, 2023 5:08 pm

Hi, our experience with these slimmer tubes (T5 and ultraslim) is that LED tubes are not particularly compatible with the transformers in the relevant light fittings. Many manufacturer’s of LED T5 tubes require that the fittings are even re-wired to bypass the transformers, which is a complete headache. For this reason, we do not stock LED T5 tubes. Our advice would be to stick with fluorescent, or swap out the fittings entirely for integrated LED fittings.

0 Reply Jon Phillips May 5, 2023 5:22 pm

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.

0 Reply Mat @ Lightbulbs Direct Author Reply to Jon Phillips May 10, 2023 9:08 am

Hi Jon, you can replace with this Crompton Lamps Fluorescent 1149mm T5 Tube 54W HO High Output Cool White.

0 Reply Steve Murphy February 22, 2023 8:56 am

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Steve Murphy February 28, 2023 3:24 pm

Hi Steve, yes, UV tubes use the same technology as fluorescent tubes, so need to be controlled by a ballast and starter to work. The easiest way would be to purchase 5x fluorescent T8 battens in the length you require, then you can simply mount the battens to your light box and insert the tubes into them. We do not sell said battens, but a quick search on google and you will find many DIY stores that sell them for £12-18 each for a 5ft length.

0 Reply pAUL January 28, 2023 7:02 pm

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?

0 Reply Mat @ Lightbulbs Direct Author Reply to pAUL February 2, 2023 4:16 pm

To deduce, if its a new tube and a new starter, then the only other variable is the ballast in the fitting, which must be failing.

0 Reply RICHARD September 27, 2022 3:11 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to RICHARD September 29, 2022 10:45 am

Hi Richard, nothing that we sell – but you may find other sellers with this item by searching Google

0 Reply David Hebden Reply to RICHARD August 11, 2023 11:26 am

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

0 Reply Elizabeth August 24, 2022 2:53 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Elizabeth August 24, 2022 3:46 pm

Hi Elizabeth, this Crompton Lamps Fluorescent 2ft T8 Tube 18W Triphosphor White F18W/835 should be the same.

0 Reply David Blakeslee July 18, 2022 4:59 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to David Blakeslee July 19, 2022 9:11 am

Hi David, that is an unusual size and we don’t offer anything that matches. Searching around the internet it looks like the tube you are after is a Philips branded tube, part number 046677417277, but I’m not seeing many sellers of this item, I feel it has probably been discontinued. You may be best advised to upgrade your kitchen lighting and we do offer a range of under cabinet kitchen lights, if you choose that option.

0 Reply Sue June 23, 2022 4:23 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Sue June 28, 2022 11:14 am

Not quite sure, as your measurements are not the same, but this is the only Crompton 13W fluorescent tube 835 we stock

0 Reply Ken March 24, 2022 5:35 pm

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

0 Reply Chris B. February 4, 2022 8:09 pm

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?

0 Reply Mat @ Lightbulbs Direct Author Reply to Chris B. March 10, 2022 1:48 pm

Hi Chris, please visit out Contact Page. Alternatively – is Sylvania Fluorescent 29″ T8 Tube 16W Warm White what you are looking for?

0 Reply Richard Latham September 9, 2021 12:38 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Richard Latham September 10, 2021 12:00 pm

For a fluorescent tube – inside the tin housing is a transformer and starter gear, which could get hot so would not be advisable to hide inside a wall. Also fluorescent tubes must be connected at both ends. Have you considered an LED tube? They can be connected to one side only and can be powered straight from mains without the need of a transformer or starter.

0 Reply Ralph October 9, 2020 8:59 am

Dose the fluorescent tube size include the pins

0 Reply Mat @ Lightbulbs Direct Author Reply to Ralph October 9, 2020 9:30 am

If you check the specifications on our product pages such as this Fluorescent T8 5ft 36W tube, you will see we state the length with and without pins. But generally, there is no variance between lengths. i.e. a 5ft tube fits all 5ft fittings, you won’t find a 5 1/2 foot or a 4.8 foot for example. You can also match by the wattage, for example all T8 tubes that are 36W are also 5ft – this is because the length of the tube is directly proportionate to the wattage. So if your old tube was 36W, just buy a new 36W tube (or a 36W equivalent LED alternative).

-1 Reply Teres August 15, 2020 5:24 pm

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

0 Reply Mat @ Lightbulbs Direct Author Reply to Teres August 28, 2020 11:29 am

Sometimes the colour is written in different ways. Look out for 3000K, 4000K, 6000K or 6500K which denotes the colour temperature in Kelvins. These can sometimes be written as 830, 840, 860 or 865 – where the 8 denotes that a triphosphor coating is used with a colour rendering index of 80+ and the next two digits are the first two digits of the colour temperature. Lastly, what is the colour of the light to look at; is it yellowish (3000K/830), white (4000K/840) or bluish (6500K/865).

0 Reply Steve June 28, 2020 10:30 am

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.

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