{"id":581,"date":"2026-10-21T16:17:58","date_gmt":"2026-10-21T08:17:58","guid":{"rendered":"http:\/\/www.winmasterind.com\/blog\/?p=581"},"modified":"2026-10-21T16:17:58","modified_gmt":"2026-10-21T08:17:58","slug":"what-is-the-size-of-a-b22-bulb-4d7e-653dab","status":"publish","type":"post","link":"http:\/\/www.winmasterind.com\/blog\/2026\/10\/21\/what-is-the-size-of-a-b22-bulb-4d7e-653dab\/","title":{"rendered":"What is the size of a B22 bulb?"},"content":{"rendered":"

Hey there! If you\u2019ve ever bought light bulbs, you\u2019ve probably seen that weird \u201cB22\u201d label on the packaging and thought, \u201cWait, what even does that mean? Is that how big it is?\u201d As someone who\u2019s been a B22 bulb supplier for over 7 years, I get so many questions about this\u2014most of them being exactly that last one: what\u2019s the actual size of a B22 bulb? Let\u2019s break it down straight, no confusing engineering jargon, just the real stuff you need to know, plus a few pro tips from someone who deals with these bulbs every single day. B22 Bulb<\/a><\/p>\n

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First off, let\u2019s get one tiny thing out of the way: a lot of folks mix up the socket size with the bulb size, but when we say \u201cB22,\u201d we\u2019re talking about the socket first and the bulb\u2019s base as part of that. Wait, hold on\u2014let\u2019s clarify. The \u201cB\u201d here stands for \u201cbayonet\u201d (you know, the push-twist base you click into place, way more common in the UK, Australia, New Zealand, and parts of Asia than the screw-type E27 you see a lot in the US). The \u201c22\u201d is the magic number everyone\u2019s curious about, and no, it\u2019s not the bulb\u2019s height or how many watts it is. Nope, it\u2019s the diameter of the bayonet base in millimeters. That\u2019s it. So the metal part that slots into your light fixture\u2019s socket is 22mm across. Got that? Let\u2019s make it relatable\u201422mm is roughly 0.87 inches, so just under 9\/10 of an inch if you\u2019re used to imperial measurements. That\u2019s the core size of the B22 base, which is what most people actually mean when they ask about the bulb\u2019s size.<\/p>\n

But wait, here\u2019s where I see people mess up all the time: the base size isn\u2019t the whole bulb. You can have B22 bulbs that are tiny little nightlights sticking out less than 2 inches, or big bright 100W equivalent LED bulbs that stretch 5 inches long, and both still fit the same B22 socket. So when someone asks \u201cwhat\u2019s the size of a B22 bulb,\u201d I always follow up with \u201care you asking about the base, or the overall bulb length?\u201d Because both matter for fitting in your light fixture. Let\u2019s cover both, since that\u2019s what actually matters for you as a buyer.<\/p>\n

Starting with the base again, because that\u2019s the non-negotiable part. B22 bases aren\u2019t just a 22mm circle\u2014they have those two little vertical pins on opposite sides, right? That\u2019s what you align with the notches in the socket, push the bulb in, twist 90 degrees, and it locks. Those pins are spaced exactly 180 degrees apart, and the base\u2019s total width (including the pins, wait no\u2014wait, no, let\u2019s get this right. The 22mm is the diameter of the circular part of the base without the pins. The pins themselves add a tiny bit, like a few millimeters each, so total width with pins is around 28mm. But the socket is cut to fit that 22mm circle and the pin spacing, so as long as the base is B22, it\u2019ll clip in. I\u2019ve had a guy come to me once saying his new bulb wouldn\u2019t fit, and he\u2019d bought a B22, turns out he\u2019d measured the pins instead of the base\u2014classic mistake.<\/p>\n

Now, the overall bulb dimensions. This is the part that varies the most, because of what the bulb is designed for. Let\u2019s go through common types, since that\u2019s what most people care about. The standard old incandescent B22 bulbs\u2014you know, the warm yellow ones that burn out in a year\u2014were usually called \u201cA60\u201d or \u201cGLS\u201d (general lighting service). Those A60 bulbs have a maximum diameter of 60mm (that\u2019s about 2.36 inches) and a total length from the bottom of the base to the top of the glass of around 105mm, or 4.13 inches. That\u2019s the classic size that fits almost all standard B22 ceiling lights, table lamps, wall sconces\u2014you name it. But LED versions of these GLS bulbs? They\u2019re way shorter, right? Manufacturers make them with smaller heatsinks so they fit in tight spaces. I\u2019ve got a standard 10W LED B22 GLS that\u2019s only 80mm long, same base, fits in every fixture that takes the old incandescents.<\/p>\n

Then there are other types: B22 golf ball bulbs (those round little ones for bathroom vanity lights or accent lamps). Those are like G30 or G45 bulbs, so their diameter is 30mm or 45mm, total length around 70mm for G45, way smaller than the standard GLS. Then you\u2019ve got reflector bulbs, like PAR20 or PAR30, for spotlights or floodlights. Wait, do those come in B22? Yeah, a lot of outdoor security lights or track light fixtures use B22 bases for PAR20s, which have a diameter of 50mm and a length around 80mm. I\u2019ve also worked with B22 candle bulbs for chandeliers\u2014those are tiny, like E12 size but in B22, with a pointed top, total length around 100mm, base still 22mm.<\/p>\n

Here\u2019s a common headache for customers: if you\u2019re replacing a bulb, never just buy \u201cB22\u201d without checking if the overall length fits your fixture. I had a customer last month who bought a set of bright B22 floodlights for his backyard, and they stuck out so far they hit his patio umbrella. Turns out he didn\u2019t check the length\u2014those PAR30 B22s were 120mm long, way longer than the 80mm PAR20 he\u2019d had before. So always, always check two things: base size is B22, and overall length of the bulb is less than the space in your fixture between where the base sits and the top of the socket housing, or the clearance above the bulb. That\u2019s the biggest mistake I see new buyers make.<\/p>\n

Wait, let\u2019s get back to the official specs for anyone who wants the hard numbers, no guesswork. The International Electrotechnical Commission (IEC) is the group that sets the global standards for these bulb bases, right? They define the B22 base as having a nominal diameter of 22mm, a pin center distance of 12.7mm, and the base\u2019s total height (the part that slots into the socket) is around 10mm. That\u2019s the official spec, so any legitimate B22 bulb will fit a B22 socket that meets IEC standards. The confusion only comes when unbranded, cheap bulbs skip the exact measurements, but as a supplier, I make sure every single B22 bulb we send out hits those IEC specs, so you don\u2019t have that fit issue.<\/p>\n

I should also mention: there are variations, but they\u2019re not common. You might see something called \u201cB22d\u201d which is a double-contact bayonet, but that\u2019s for industrial bulbs or specialized applications, not the household B22 most people buy. Stick to standard B22 unless you know you need the extra contact.<\/p>\n

Now, why does this matter for you, the buyer or someone looking for bulbs? If you\u2019re replacing a bulb, knowing the base is B22 means it\u2019ll fit your existing fixture, but checking diameter and length means it won\u2019t be too big or stick out weird. If you\u2019re buying for a new build or renovating, making sure all your sockets are B22 (instead of E27, which is super common in the US) saves you from a hassle later. I\u2019ve had contractors come to me because they mixed up E27 and B22 sockets on a house job\u2014cost them time and money to replace all the sockets, so trust me on that part.<\/p>\n

As a B22 bulb supplier, I\u2019ve tested hundreds of bulbs over the years, and the only consistent number is that 22mm base diameter. Everything else is up to the bulb\u2019s purpose, so don\u2019t panic if one B22 bulb is twice as long as another. The best way to measure if a bulb will fit is to either take your old bulb to the store (or pull up a pic) or measure the interior of your fixture: the distance between the base opening and the highest point the bulb can reach, plus the space around the sides. If a bulb\u2019s diameter is less than that side space and its length is less than the fixture\u2019s internal depth, it\u2019ll work.<\/p>\n

Wait, let\u2019s do a quick side-by-side to make it super clear:<\/p>\n