IKEA BILLY: Complete LEGO Display Guide (2026)
How do you display LEGO on BILLY bookcase?
Choose the 39cm (15") depth BILLY, adjust shelves to match your set heights, add OXBERG glass doors for dust protection, and install LED lighting. The adjustable shelf system accommodates everything from small Creator sets to tall modular buildings, making BILLY the most versatile LEGO display solution available.
Why BILLY is Perfect for LEGO Collectors
Walk into any serious LEGO collector's home and you'll probably see at least one BILLY bookcase. Some have walls of them. There's a reason this simple Swedish bookcase has become the unofficial standard for LEGO displays.
BILLY just works. The shelves adjust to fit everything from tiny Architecture sets to massive modular buildings. You can start with one unit and add more as your collection grows (and let's be honest, it will grow). And at under €100 per unit, you're spending money on LEGO instead of expensive custom furniture.
The secret is the adjustable peg system. Unlike fixed shelves that force you to work around awkward gaps, BILLY adapts to your collection. Building the Daily Bugle? Remove a shelf and create the tall space you need. Displaying a bunch of Speed Champions? Space the shelves closer together. It's furniture that works for you, not the other way around.
1. Choosing the Right BILLY Setup
Source: Ikea.com
The Most Important Decision: Depth
BILLY comes in two depths, and this choice matters more than anything else:
28cm (11") depth - The standard version. Works fine for books and most regular LEGO sets, but you'll feel limited pretty quickly. Small sets look lost pushed to the back, and larger builds simply won't fit.
39cm (15") depth - This is what you want. Here's the thing: it costs basically the same as the 28cm version, but it changes everything. You can fit modular buildings comfortably. UCS sets that wouldn't work in the shallow version? They fit here, sometimes even at an angle for visual interest. You can display multiple small sets per shelf without them looking cramped.
Unless your room literally can't accommodate the extra 11cm of depth, always go with 39cm. You won't regret it.
Width Options
BILLY comes in three widths:
- 40cm (16") - Narrow and perfect for hallways or tight spaces, but limited display area
- 80cm (31") - The sweet spot. Wide enough for impact, narrow enough to fit most rooms
- 120cm (47") - Maximum display space for dedicated LEGO rooms
Most collectors start with one or two 80cm units. It's the Goldilocks option—just right.
Height Choices
You've got three height options, and this depends on your ceiling and ambitions:
- 106cm (42") - Short version, works under windows
- 202cm (79") - Standard height, fits most rooms perfectly
- 237cm (93") - Standard + extension unit for floor-to-ceiling drama
The extension units are impressive if you've got the ceiling height. They add 35cm and transform BILLY from furniture into a statement wall. Just remember: taller units absolutely require wall anchoring.
Combining Multiple Units
Source: Ikea.com
Here's where BILLY really shines. You can line up multiple units to create a continuous display wall. Three 80cm units give you 240cm (nearly 8 feet) of display space—enough for a serious collection.
When you combine units, assemble them in position, then connect them at the back with L-brackets. This keeps them aligned and prevents gaps from opening up. Anchor the entire combined setup to the wall as one piece, not individually.
Popular combinations:
- Two 80cm units (starter setup, 160cm total)
- Three 80cm units (most common, 240cm wall)
- 120cm + 80cm (asymmetrical but interesting)
- L-shaped corner with a 40cm and 80cm perpendicular
2. What Actually Fits in BILLY
This is the question everyone asks, so let's get specific.
The Depth Factor
Remember how we said 39cm depth is the way to go? Here's why in practical terms:
The 28cm depth handles most standard LEGO sets fine—your typical Star Wars ships, Creator 3-in-1 builds, Architecture series, Speed Champions. But it can't accommodate large modular buildings on baseplates, bigger UCS sets, or deep Technic models. You'll constantly be working around limitations.
The 39cm depth fits everything the 28cm can, plus modular buildings (which are about 25x25cm on a 32x32 baseplate), most UCS sets, Ideas sets, and Technic builds. You can also display sets at angles for visual interest, or put multiple small sets front-to-back on one shelf.
The only things that won't fit even in 39cm BILLY are the absolute monsters: UCS Millennium Falcon (84cm diameter), UCS Star Destroyer (110cm long), and the massive UCS AT-AT. Those need dedicated tables or wall shelves. You can even fit The Lord of the Rings Rivendell set when places on the proper angle.
Theme-by-Theme Breakdown
Modular Buildings - This is where BILLY at 39cm depth really shines. A standard modular on a 32x32 baseplate is about 25x25cm—it fits perfectly with room to spare. You can fit one modular per shelf section on the 80cm width, or two on the 120cm width. The height works out perfectly too, with most modulars being 30-32cm tall. Set your shelves to 35-40cm spacing and you're golden.
UCS Sets - Most work, but you need to know which ones. The UCS A-Wing, Y-Wing, TIE Fighter, Snowspeeder, and Razor Crest all fit in the 39cm depth. The Y-Wing and TIE Fighter are right at the edge (31cm deep) but you can angle them slightly to make them work. The massive ones like the Falcon, Star Destroyer, and AT-AT won't fit—don't even try.
Creator Expert and Icons - Almost everything in these lines works beautifully. The Daily Bugle is the tallest at about 82cm, so you'll need to remove a shelf or two to create the clearance (aim for 90cm of height). The Boutique Hotel, Police Station, and similar sets are ideal BILLY residents.
Architecture Series - Perfect fit for BILLY. Most Architecture sets are compact and designed to be displayable. The Eiffel Tower and Burj Khalifa are the tall ones that need 60-70cm of vertical clearance, but the 39cm depth handles them fine.
Technic - Here's where you need to check dimensions case-by-case. Some Technic models are surprisingly deep. Measure before assuming it'll fit.
Shelf Spacing Strategy
The beauty of BILLY is the adjustable shelves. The holes are spaced every 3.2cm (about 1.25"), so you can dial in the exact height you need.
For small sets (10-20cm tall) like Speed Champions or small Creator builds, space shelves 25-28cm apart. This gives breathing room and prevents a cluttered look. You can fit 3-5 sets across an 80cm shelf.
For medium sets (20-35cm tall) which is most of your standard LEGO collection, go with 38-42cm spacing. You'll fit 1-2 sets per shelf depending on width.
Modular buildings work best at 35-40cm spacing. Most modulars are 30-32cm tall, and that extra space above prevents the roofs from feeling cramped.
Large sets (35-50cm) need 50-60cm of clearance. At this point you're usually displaying one set per shelf, and that's fine—they deserve the spotlight.
For the extra-large sets like the Daily Bugle or Eiffel Tower, you're looking at 60-90cm of height or just removing a shelf entirely to create a double-height space.
Pro tip: For your most valuable or delicate sets, consider using acrylic display cases. They add protection while maintaining full visibility, and the case height is consistent regardless of shelf spacing.
3. Upgrades and Protection
OXBERG Glass Doors - The Dust Solution
Source: Ikea.com
Let's talk about dust, because it's the silent enemy of LEGO displays. Those horizontal surfaces and detailed builds are dust magnets, and cleaning intricate LEGO sets is tedious.
OXBERG glass doors solve this completely. You get two glass doors per set (€60-80 depending on width), they have soft-close hinges so they don't slam, and the glass is clear enough that it barely affects visibility. Once they're on, dust accumulation drops to basically zero.
The downside? Access. If you're the type who likes to frequently rotate your display, rearrange sets, or handle your builds, doors become a minor hassle. You have to open them every time.
Here's an alternative approach a lot of collectors use: skip the doors entirely and use acrylic display cases for your most valuable sets. This gives you protection exactly where you need it (retired sets, expensive UCS builds, delicate pieces) while keeping the rest of your collection easily accessible. Best of both worlds.
You can always add OXBERG doors later if you decide you want them, so don't feel pressured to buy them immediately.
Height Extensions
Extension units add 35cm of height, bringing total height to 237cm (over 7.5 feet). This creates genuine floor-to-ceiling impact and is perfect if you've got the ceiling height and a serious collection.
Two things to know: extensions absolutely require wall anchoring (a tall, loaded BILLY is a tipping hazard), and they're easier to install during initial assembly than trying to add them later.
4. Making It Look Amazing
Creating Focal Points
Not every set deserves equal attention. Create a hierarchy.
Your hero set—the one you're most proud of, your latest complicated build, your white whale that you finally got—should be at eye level (roughly 140-170cm from the floor). This is where people's eyes naturally land. Center it on that middle shelf.
Strategic empty space is just as important as the sets themselves. Don't pack every square centimeter. When a shelf feels full, you're probably at about 70% of capacity—and that's perfect. That remaining 30% gives everything room to breathe and draws attention to what's actually there.
Think of it this way: a museum doesn't cram paintings together. Space creates focus. Same principle applies to LEGO.
Common Problems and Quick Fixes
Shelf sagging? Move your heavy UCS sets toward the sides where the supports are, and spread heavy sets across multiple shelves rather than loading everything on one. Place lighter sets in the middle of shelves.
Dust driving you crazy? Either commit to OXBERG doors for complete protection, or grab acrylic display cases for your most valuable sets and dust the rest monthly with a soft brush or air duster.
Wobbling? This one's serious: anchor BILLY to the wall. It's not optional, especially when it's loaded with heavy LEGO. Use the anchors that come with it, or get proper wall anchors from a hardware store if you have drywall. A fully-loaded BILLY can tip, and that's dangerous.
Sets too tall? Remove a shelf to create a double-height space. The fixed shelf (one that came pre-attached) limits you, but you can work around it by planning tall sets for the spaces above or below it.
Quick FAQ
Should I get 28cm or 39cm depth?
39cm, always. It costs the same and gives you so much more flexibility. Only go 28cm if your room literally can't fit the deeper version.
How many sets can I fit?
On an 80cm width BILLY: roughly 15-25 medium sets, 30-40 small sets, or 8-12 large sets. But plan for less—breathing room looks better than maximum density.
Do I really need glass doors?
If dust annoys you or you have pets/kids bumping into things, yes. If you like easy access and don't mind occasional dusting, no. Middle ground: use acrylic display cases for your valuable sets only.
BILLY or KALLAX for LEGO?
BILLY for collections with varying set heights (the adjustable shelves are the whole point). KALLAX for modular buildings or if you love the cube aesthetic. Honestly, most serious collectors end up with both.
How do I stop shelves from sagging?
Place heavy UCS sets near the sides where the supports are, not in the middle. Spread heavy sets across multiple shelves. Use the 39cm depth version—it's stronger than 28cm. If you see sagging start, redistribute weight immediately.
Can I customize BILLY?
Absolutely. Painting the back panel is the easiest mod—black, navy, or charcoal make LEGO colors pop. Some people add wallpaper, fabric backing, or even custom printed scenes. Get creative.
Final Thoughts
BILLY isn't just a bookcase—it's a system that grows with your collection. Start with one or two units and see how it works for your space and style. You can always expand later, add extensions, combine multiple units, or upgrade with doors and lighting.
The key decisions: choose 39cm depth, plan your shelf spacing around your tallest sets first, and don't overfill your shelves. Everything else is just fine-tuning to match your preferences.
Protect what matters: Browse our acrylic display cases designed specifically for LEGO collectors—from modular buildings to UCS sets, we've got the perfect protection for your builds.
Now go make that IKEA run. Your LEGO collection deserves better than sitting in boxes or gathering dust on random shelves. Give it the display it deserves.