IKEA Billy shelf pin sizes

white billy bookcases set up in a living room
This is maybe the least interesting post I’ve ever written. But as said before, I like to contribute knowledge back to the internet when it’s been hard to find.

To summarize up top:

  • Older Billy bookcases use 5mm shelf pins.
  • Current Billy bookcases (as of 2022) use 3mm (or maybe 4mm) shelf pins.


I love Ikea’s Billy bookcases. They’re not fancy, but class em up with some lights and creative displays, and you can’t beat performance for the price.

I recently needed to replace some shelf pegs (or shelf pins? terminology varies), those little metal things that hold up each shelf. And I made a minorly distressing discovery: IKEA has changed the size of the pegs.

I don’t know when this happened, but Billys (Billies?) I bought in 2018 use 5mm pegs/pins. A Billy that I bought recently in 2022 uses a roughly 3mm peg/pin. I say “roughly” because the generic brand 3mm pins I bought are a little loose in the holes. But they still hold up a shelf fine. I think a 4mm peg/pin would be ideal, but they’re also much less commonly sold than 3mm.

Of course, the best option is to go back to Ikea and ask them for some free spare parts. But that’d be a 5 hour trip for me, so I’m happy enough with the substitute.