Updated September 16, 2026 — by César, editor at AestheticPoster
Framing a poster comes down to three decisions: frame size (the smallest commercial size that holds it), glass or plexiglas (half the weight), and a mat as soon as the margin exceeds 2 cm. Installation takes ten minutes.
Key takeaways
- No commercial frame fits a poster's exact size: M 30×42, L 42×60, and XL 60×84 cm fit into a 40×50, 50×70, and 61×91 cm frame, leaving margins to manage.
- Plexiglas weighs half as much as glass (2.4 vs. 5 kg/m² in 2 mm): crucial for XL sizes, children's rooms, or humid spaces.
- Never glue a poster across its entire surface: two adhesive hinges at the top are enough.
What frame size for which poster?
Our posters follow the A-series proportions (M ≈ A3, L ≈ A2, XL ≈ A1), while commercial frames come in round sizes inherited from photography. They never match:
| Poster format | Smallest common frame that holds it | Margin per side (width / height) | Mat needed? |
|---|---|---|---|
| M 30×42 cm | 40×50 cm | 5 cm / 4 cm | Yes |
| L 42×60 cm | 50×70 cm | 4 cm / 5 cm | Yes |
| XL 60×84 cm | 61×91 cm | 0.5 cm / 3.5 cm | Optional |
Common pitfall: a 30×40 cm frame looks like it's made for an M, but it's 2 cm too short in height. Check the inner height, not just the width. The IKEA frame compatibility chart lists the ranges that work; the M, L, XL format guide helps you choose size based on wall space. To avoid the issue: the framed version, pre-adjusted frame, ready to hang.
Glass or plexiglas for the pane?
In 2 mm, mineral glass weighs about 5 kg/m² (2.5 kg on an XL of 0.5 m²), plexiglas 2.4 kg/m². Glass resists scratches and gives the sharpest image, but breaks into shards; plexiglas won't shatter, scratches more easily, and cleans with warm water and a microfiber cloth—no ammonia. Glass for M and L, plexiglas for XL, children's rooms, or bathrooms. Neither filters UV without treatment: see protecting a poster from sun and fading.
What about direct canvas printing or printing under plexiglas? We don't offer it. Canvas smooths the grain and loses detail in flat colors; acrylic printing costs two to three times as much as a framed poster, reflects light, scratches, and can't be replaced without buying everything again. Matte poster paper at 250 g/m² under glass keeps the sharpness with no glare, and swaps out in two minutes: the best quality-to-price ratio.
Do you need a mat, and how wide should it be?
This thick cardboard with a cutout window absorbs the size difference with the frame, highlights the image, and keeps paper from touching the glass. Beyond 2 cm of margin per side, it's essential; below that, the poster centered on the backing board is enough. A 4 to 6 cm border for M and L, 6 to 8 cm for XL. Acid-free cardboard (neutral pH) is mandatory: the French National Library notes that acidic cardboard yellows paper in a few years. Window: 30×42, 42×60, or 60×84 cm minus 3 to 5 mm per side, to slightly overlap the edge.
Installation in five steps
- Flatten the poster if it arrives rolled: 24 to 48 hours under a stack of books, never with an iron (full method).
- Clean the glass on both sides with a microfiber cloth, then handle the poster by the edges only, with dry hands.
- Secure with two adhesive hinges at the top, on the back (archival tape or gummed paper): the paper must hang freely to avoid warping.
- Stack glass, mat with the poster, backing board; check alignment, close the tabs.
- Hang the center of the image at 1.52 m from the ground (the 1.52 m rule, hardware in how to hang a poster). After that, dry dusting is all you need (maintenance).
How much does framing a poster cost?
| Option | What it includes | Price | Best for |
|---|---|---|---|
| Poster delivered framed | Frame in exact size, black, white, light wood, or dark wood | M 69.99 € (+50 €) · L 99.99 € (+70 €) · XL 149.99 € (+100 €) | Zero research, guaranteed result |
| Commercial frame + DIY installation | 40×50 / 50×70 / 61×91 cm frame, mat for M and L | Poster 19.99 / 29.99 / 49.99 € + frame | Tight budget |
| Custom framing service | Frame, UV-protective glass, mat cut to exact size | Poster + quote | Valuable poster |
For M, the +50 € framed version rarely loses to an equivalent commercial frame plus mat. For L and XL, the gap narrows; for a wall of frames, mixing framed and unframed brings the cost down.
FAQ
What frame size for an A3 or 30×42 cm poster?
The 40×50 cm, with 4 to 5 cm of margin per side filled by a mat. The 30×40 cm, often sold as "A3 format," is 2 cm too short in height.
How do I hang a poster in a frame without damaging it?
Using two archival adhesive hinges at the top, on the back, on the mat or backing board. Never glue across the entire surface or on the printed side: the installation must remain reversible.
Framed poster, canvas, or plexiglas: which should I choose?
Matte poster paper, framed: detail intact, no glare, image replaceable without changing the frame. Canvas softens flat colors; acrylic costs two to three times more and scratches. We print only on paper.
All posters in the Décoration collection come in M, L, and XL, unframed or framed — and here's why our posters are matte.
César, editor at AestheticPoster — the mistake I see most often isn't the frame, it's the adhesive: a poster glued across its entire surface warps at the first humidity change.
