Updated August 4, 2026 — by César, editor at AestheticPoster
No IKEA frame matches A3, A2, or A1 formats exactly: its range follows round sizes in centimeters (30×40, 40×50, 50×70, 61×91 cm), not the ISO 216 standard for posters. The closest format to an existing frame is A1 in 61×91 cm (gap of 8 mm in width, 3.5 cm in height); both A3 and A2 require a mat for a clean finish.
Key takeaways
- The 30×40 cm frame, often presented as IKEA's « A3 size », is actually 2 cm too short for an A3 poster (297×420 mm) — a common trap to avoid.
- For an A3 (297×420 mm), the smallest IKEA frame that truly fits it is the 40×50 cm, with a border of 4 to 5 cm depending on the side.
- For an A2 (420×594 mm), the 50×70 cm is the reference, with 4 cm border in width and 5.3 cm in height.
- For an A1 (594×841 mm), the 61×91 cm is the best fit of the three formats: only 8 mm clearance in width.
- AestheticPoster's 250 g/m² paper is identical in A3, A2, and A1, in matte or glossy finish: frame choice affects neither price nor print quality.
Why do IKEA frames never match A3/A2/A1 formats exactly?
Two different standards coexist. Posters in A3, A2, or A1 format follow the ISO 216 standard: each format is exactly half the previous one, with a constant ratio of 1:1.41 between width and height. IKEA, like most home decor chains, uses a scale of round sizes in centimeters inherited from film photography: 21×30, 30×40, 40×50, 50×70, 61×91, 70×100 cm, with ratios close to 4:3 or 5:4. The two scales never align exactly, and the ratio discrepancy widens as the size grows.
| Poster format (ISO 216) | Exact dimensions | Smallest IKEA frame that fits it | Border (width / height, per side) |
|---|---|---|---|
| A3 | 297 × 420 mm | 40 × 50 cm | 5.2 cm / 4 cm |
| A2 | 420 × 594 mm | 50 × 70 cm | 4 cm / 5.3 cm |
| A1 | 594 × 841 mm | 61 × 91 cm | 0.8 cm / 3.5 cm |
The 30×40 frame trap for an A3 poster
This is the most common mistake: the 30×40 cm frame (300×400 mm) seems made for A3 (297×420 mm) because its width matches to the millimeter (300 mm versus 297 mm). But its height, 400 mm, is 20 mm shorter than the poster: an A3 simply won't fit in this frame, regardless of orientation. This is true for all IKEA frame ranges available in this size: RÖDALM, LOMVIKEN, SILVERHÖJDEN, FISKBO, KNOPPÄNG. Always check the frame height, not just the width, before buying.
Which IKEA frame for an A3 poster (297×420 mm)?
The smallest IKEA frame that truly contains an A3 is the 40×50 cm. The resulting border is not symmetrical: approximately 5.2 cm on each side in width, 4 cm top and bottom. Two ways to handle this gap:
- Custom mat with 297×420 mm window: the cleanest result, uniform visual border even if the raw dimensions differ slightly between width and height.
- Mounting without mat, poster centered on the frame's background: works especially well if the background is neutral (white, light oak) and the slight asymmetry (5.2 cm versus 4 cm) remains subtle.
Which IKEA frame for an A2 poster (420×594 mm)?
The 50×70 cm is the reference for A2. The difference is 4 cm in width and 5.3 cm in height per side — similar to the A3 case, so the same solutions apply: custom mat with 420×594 mm window for sharp framing, or direct mounting on a neutral background, accepting the visible border. The 40×50 cm, smaller, won't work: its width (400 mm) is less than A2 width (420 mm) and cuts off the poster.
Which IKEA frame for an A1 poster (594×841 mm)?
The 61×91 cm is the best fit of all three formats: only 8 mm border per side in width, and 3.5 cm in height. It's also the largest common size in stores, beyond the 70×100 cm reserved for XXL prints. An A1 poster intended to become the focal point of a wall works well with this combination: simply center it on the frame's background, the remaining border in height (3.5 cm per side) stays subtle without a mat, or add a thin one for a gallery effect.
Do you always need a mat for an IKEA frame?
Not necessarily, but in most cases here. Only A1 in a 61×91 cm frame reasonably gets by without one, thanks to its tight border. For A3 (40×50 cm) and A2 (50×70 cm), the border exceeds 4 cm per side: without a mat, the poster looks « floating » and poorly centered if mounting isn't careful. Simple rule: beyond 2 cm border per side, a mat significantly improves the look.
FAQ — IKEA frames and poster formats
Does the IKEA 30×40 frame work for an A3 poster?
No: its height (400 mm) is 20 mm shorter than an A3 (420 mm), the poster won't fit. The smallest IKEA frame that truly contains an A3 is the 40×50 cm, with a mat or mounting on neutral background to manage the 4 to 5 cm border.
Does an A2 poster fit in an IKEA 50×70 frame?
Yes, with a border of 4 cm in width and 5.3 cm in height per side if the poster is simply laid on the background. A custom mat with 420×594 mm window gives a cleaner result.
What IKEA frame size for an A1 poster?
The 61×91 cm, the largest common size in stores, and the best fit of all three A3/A2/A1 formats: only 8 mm border in width and 3.5 cm in height per side.
Why doesn't IKEA sell frames in exact A3/A2/A1 formats?
Because its range follows a scale of round sizes in centimeters inherited from photography (21×30, 30×40, 40×50, 50×70, 61×91 cm), with ratios close to 4:3, different from the 1:1.41 ratio of the ISO 216 standard for posters.
Framing an AestheticPoster
AestheticPoster's 250 g/m² paper is identical in A3 (297×420 mm), A2 (420×594 mm), and A1 (594×841 mm), in matte or glossy finish: frame choice affects neither price nor print quality. Browse our decoration posters to find the right visual for the frame size you already have, or consult our complete buying guide to compose a cohesive wall.
César, editor at AestheticPoster — I measured IKEA frame rabbets against ISO formats before writing this guide, including the 30×40 frame.
