{"id":3515,"date":"2026-10-09T08:43:57","date_gmt":"2026-10-09T00:43:57","guid":{"rendered":"http:\/\/www.ylevacase.com\/blog\/?p=3515"},"modified":"2026-10-09T08:43:57","modified_gmt":"2026-10-09T00:43:57","slug":"how-to-choose-the-right-via-size-in-a-pcb-4482-d2e1af","status":"publish","type":"post","link":"http:\/\/www.ylevacase.com\/blog\/2026\/10\/09\/how-to-choose-the-right-via-size-in-a-pcb-4482-d2e1af\/","title":{"rendered":"How to choose the right via size in a PCB?"},"content":{"rendered":"

Hey there, it\u2019s Mia from your go-to PCB supplier\u2014let\u2019s cut the corporate jargon for a sec, because I know choosing the right via size for your board can feel like picking a random number out of a hat when you\u2019re knee-deep in design. I\u2019ve seen it all over the years: a designer grabs a standard 0.2mm via because \u201cthat\u2019s what I always use,\u201d only to hit soldering issues, signal loss, or even board costs blowing out way more than they needed to. Today we\u2019re breaking this down like we\u2019re chatting over coffee, no stuffy textbooks required\u2014just real, tested tips from folks who\u2019ve built thousands of boards for everything from smart watches to industrial power systems. PCB<\/a><\/p>\n

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First, let\u2019s make sure we\u2019re on the same page: a via is just that little hole in your PCB that connects copper layers together, right? Some are through-hole (go all the way through the board), blind (connect top layer to an inner layer), or buried (only inner layers). But size\u2014when we talk about via size, we\u2019re not just talking the hole diameter. It\u2019s the drill size, the finished hole size, the annular ring (the copper around the hole), and even the land pad size. I can\u2019t tell you how many times a designer will pick a drill size and forget the annular ring is too small, leading to copper peeling off when the board gets assembled. Annular ring is non-negotiable here\u2014you need at least 0.1mm of copper around the whole hole, no exceptions. If your drill is 0.2mm, the finished hole is basically that minus a tiny margin for plating, so let\u2019s say 0.18mm. Then your annular ring needs 0.1mm on every side, so total pad size is 0.18mm + 0.1mm + 0.1mm = 0.38mm. A lot of cheap EDA tools won\u2019t call that out, but trust me, we\u2019ve rejected tons of boards over that small detail.<\/p>\n

Let\u2019s start with the most common constraint everybody faces: board size and layer count. If you\u2019re building a tiny board for a fitness tracker, your overall real estate is limited\u2014you can\u2019t use a big 0.8mm via because there\u2019s no space. That\u2019s when you go micro-vias, right? Micro-vias are under 0.15mm drill size, and they\u2019re drilled with laser, not mechanical bits. But wait\u2014micro-vias aren\u2019t free. They cost way more to make, and they only connect one layer to an adjacent one (blind vias), so if you need to jump three layers, you might need multiple micro-vias. On the flip side, if you\u2019re doing a big industrial control board with 10 layers, you\u2019ve got room to breathe, so using a 0.4mm or 0.5mm via is totally fine. Bigger vias are more robust, easier to solder, and cheaper to manufacture because mechanical drilling of larger holes is faster than tiny ones. Pro tip: if your board is over 2 layers, count how many vias you have total. More small vias = more drill bits changing = longer lead time = higher cost. I\u2019ve had a designer trim 50 micro-vias off their 10-layer board, and their quote dropped by 15% immediately. That\u2019s the kind of win we love.<\/p>\n

Next up: electrical performance, because vias are a pain in the butt for signals\u2014they cause what\u2019s called \u201cvia stub\u201d and impedance mismatch. Stub is the extra length of the via that\u2019s not connected to the top or bottom layer, right? If you have a through-hole via that goes from top layer to layer 2, the stub from layer 2 to the bottom layer is just hanging there, creating a little antenna that messes with high-frequency signals. So for high-speed boards (anything over 1GHz, like RF gear, 5G modules, or gaming motherboards), you need smaller vias, or better yet, back-drilled vias. Back-drilling is when we drill out the extra stub from the bottom, but that only works with through-hole vias, and it\u2019s an extra step. Smaller vias have shorter stubs, so less signal degradation. I had a client a few months back who was having signal loss in their 2.4GHz router board\u2014they were using 0.6mm vias, switched to 0.3mm, and their signal strength jumped 12% without changing anything else. Game changer. Also, impedance: the via\u2019s impedance depends on its size, the surrounding copper, and the dielectric material between layers. If you\u2019re designing for 50-ohm or 75-ohm signals, a too-big via will lower the impedance too much, and a too-small one will make it too high. Most EDA tools have via impedance calculators now, but don\u2019t rely solely on that\u2014send your design to your PCB supplier, and we can run a quick check for free. We do that all the time, because a small adjustment to via size can save you from a whole spin of boards.<\/p>\n

Then there\u2019s thermal considerations, especially for power boards. If you\u2019re running high current (like 5A or more), you need vias that can handle that heat without melting or causing voltage drop. The current capacity of a via is directly tied to its size\u2014bigger via = more copper, so more current it can carry. Let\u2019s say you have a 0.5mm via, that can handle about 1A. A 0.8mm via? That\u2019s around 2.5A. If you\u2019re putting 3A through a 0.5mm via, it\u2019ll get hot enough to lift the copper pad, and that\u2019s a board failure waiting to happen. For power-heavy designs, we also recommend multiple smaller vias in parallel instead of one big one, because that spreads the current and heat better. I had a client who was designing a solar charge controller, they were using four 0.4mm vias for their power rail, we suggested swapping to six 0.3mm vias, and their operating temp dropped 8\u00b0C. That might not sound like much, but it doubles the lifespan of the board in outdoor conditions.<\/p>\n

Soldering and assembly is another big one, and this is where a lot of new designers mess up. If you\u2019re doing hand-soldering, you can\u2019t use a 0.1mm via\u2014way too tiny to get a soldering iron tip in there. Even for automated SMT assembly, your stencil size matters. The stencil aperture for a via pad needs to be big enough to let solder flow, but not so big that it wicks away from the component pads. For through-hole components, the via size has to match the lead size\u2014if your component lead is 0.3mm, your via should be at least 0.05mm bigger than that to make soldering easy. Too small, and you\u2019ll have cold joints or leads that don\u2019t fit. Also, plated through-holes (PTH) vs. non-plated vias: PTH is standard for most boards, but non-plated are for things like test points. If you\u2019re using a test point via, a 0.25mm drill is standard, but if you\u2019re going to probe it, don\u2019t make it smaller than 0.2mm or you\u2019ll damage the pad when probing. I\u2019ve seen so many boards with tiny test point vias that the assembly team can\u2019t probe, so they have to add extra test points, which adds cost. Rule of thumb: if the via is going to be handled during assembly or testing, err on the side of slightly bigger, within reason.<\/p>\n

Wait, let\u2019s talk about common mistakes I see all the time. First, using the same via size for the entire board. That\u2019s lazy! Your high-speed signals need small vias, your power rails need bigger ones, your test points can be medium size. Second, ignoring the minimum annular ring. Some designers set their annular ring to 0.05mm, which is technically what their EDA tool allows, but it\u2019s impossible to manufacture reliably. Our minimum recommended annular ring is 0.1mm, and we can do 0.07mm if it\u2019s a super tight design, but at your own risk\u2014we don\u2019t warranty boards with that. Third, not accounting for plating. When you drill a hole, we plate the inside with copper, so the finished hole is a tiny bit smaller than the drill size. So if you set your finished hole size to 0.2mm, you need to use a 0.22mm drill to get that 0.2mm finished hole. That\u2019s a detail that trips up so many people. Fourth, forgetting about the board\u2019s minimum trace width. If your board has 0.1mm traces, you can\u2019t put a 0.3mm via next to them, because they\u2019ll overlap during manufacturing. Always check the clearance between vias and traces\u2014at least 0.1mm, more if you can.<\/p>\n

Let\u2019s do a quick example to make this real. Say you\u2019re designing a 4-layer board for a Bluetooth speaker, with low-speed signals (less than 100MHz), a 2A power rail, and hand-soldered components. What via size makes sense? Let\u2019s break it down: total board size is 50x50mm, so space is tight, not tiny like a watch. No super high-speed signals, so stub isn\u2019t a big deal. 2A power rail, so we need a via that can handle at least 2.5A (for safety). Hand-soldered, so hole can\u2019t be too tiny. Let\u2019s pick a 0.3mm drill size. Finished hole will be ~0.28mm. Annular ring is 0.1mm, so pad size is 0.28 + 0.1 + 0.1 = 0.48mm. Clearance: 0.1mm from traces, so that works. Current: a 0.3mm via can handle ~1.2A, so we\u2019ll put two parallel vias for the power rail\u2014perfect, that\u2019s enough for 2A, spreads heat, and still fits on the board. Signals can use the same 0.3mm via, no need for smaller ones. That\u2019s simple, works, and won\u2019t cost you an arm and a leg.<\/p>\n

If you\u2019re working on a different design: 10-layer 5G module (high-speed, tiny, 0.5A total current). Here, micro-vias are the way to go. 0.1mm drill size, finished hole ~0.09mm, annular ring 0.08mm (we can squeeze that for micro-vias, since space is non-negotiable). Back-drill the stubs to eliminate signal loss. That gives you tiny vias that don\u2019t take up much space, keep signals clean, and handle the low current fine. The extra cost for micro-vias is worth it here, because if you used standard vias, the board would be too big for your design.<\/p>\n

One last thing: always talk to your PCB supplier before finalizing your via sizes. We\u2019ve seen every trick in the book, and we can spot issues you\u2019d never catch in your EDA tool. For example, a designer once used 0.2mm vias for a 12-layer board, and we noticed that the drill bit would break halfway through because the stackup was too thick for such a small drill. We suggested switching to 0.25mm, which was still small enough for their space constraints, and saved them from a whole batch of defective boards. We don\u2019t charge extra for that feedback\u2014it\u2019s part of the service, because we want you to come back.<\/p>\n

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If you\u2019re in the middle of a design right now, or you\u2019re starting a new project and want to avoid the headache of via size missteps, hit us up. No pushy sales talk, just honest advice to get your boards right the first time. We\u2019ve got engineers on staff who can run impedance checks, current calculations, and even mock up different via size options for your design. Let\u2019s get your board built without the surprises.<\/p>\n

PCB<\/a> References
\nIPC-2221: Printed Board Design Standard
\nIPC-7351: Generic Requirements for Surface Mount Design and Land Pattern Standard
\nHigh-Speed Signal Propagation: Advanced Black Magic, Howard Johnson<\/p>\n

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Lucky Dragon Technology Shenzhen Co., Ltd.<\/a>
With abundant experience, we are one of the most professional PCB manufacturers and suppliers in China. We warmly welcome you to buy bulk high quality PCB for sale here from our factory. If you have any enquiry about cooperation, please feel free to email us.
Address: 5th Floor, Building 1, Jinshan Industrial Park, 375, Xixiang Section, Guangshen Road, Xixiang Street, Baoan District, Shenzhen City, Guangdong Province, China
E-mail: sales@Ldtac.com
WebSite: https:\/\/www.ldtac.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Hey there, it\u2019s Mia from your go-to PCB supplier\u2014let\u2019s cut the corporate jargon for a sec, … How to choose the right via size in a PCB?<\/span>Read more<\/a><\/p>\n","protected":false},"author":52,"featured_media":3515,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3478],"class_list":["post-3515","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-pcb-47a0-d31175"],"_links":{"self":[{"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/posts\/3515","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/users\/52"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/comments?post=3515"}],"version-history":[{"count":0,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/posts\/3515\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/posts\/3515"}],"wp:attachment":[{"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/media?parent=3515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/categories?post=3515"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ylevacase.com\/blog\/wp-json\/wp\/v2\/tags?post=3515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}