A3 Poster Print Quality Checker
Standard A3 size is 297 × 420 mm (11.69 × 16.54 inches). At 300 DPI, your artwork requires a minimum of 3508 × 4961 pixels to prevent pixelation.
At 300 DPI (Gallery Sharp): Minimum 3508 × 4961 pixels.
At 150 DPI (Poster Viewing): Minimum 1754 × 2480 pixels.
A3 Print Guide
Everything you need to print A3 Poster sharp
A3 is twice the size of A4 and the go-to size for small posters, art prints, drawings, presentation boards and photo enlargements in most of the world. The closest US size is 11 × 17 inches (tabloid), which is a little narrower and longer.
At 300 DPI, A3 needs 3508 × 4961 pixels, about 17.4 megapixels. That is more than most phones save by default, but A3 prints usually hang on a wall or sit on an easel, where 200–250 DPI looks just as sharp.
A 12 megapixel phone photo works out at about 244 DPI once cropped to A3’s shape: fine for a framed print. A 24 megapixel camera photo reaches about 340 DPI, comfortably sharp even up close.
A3 at a glance
| Size | 297 × 420 mm · 29.7 × 42 cm · 11.69 × 16.54 in |
|---|---|
| Shape (aspect ratio) | 1 : 1.414 (ISO paper shape) |
| Common uses | Small posters, exhibition prints, architectural drawings, menus, wall charts. |
Pixels needed for A3
| Resolution | Pixels (width × height) | Megapixels | Best for |
|---|---|---|---|
| 300 DPI | 3508 × 4961 | 17.4 MP | Close up (photos, cards, documents) |
| 240 DPI | 2806 × 3969 | 11.1 MP | Framed and wall prints |
| 150 DPI | 1754 × 2480 | 4.3 MP | Posters viewed from a distance |
Pixel sizes are for portrait. For landscape, swap width and height.
Tips for printing at A3
- Scaling from A4 works perfectly. A3 is the same shape as A4, so an A4 design just needs enough pixels: 3508 × 4961 at 300 DPI, or 2339 × 3307 at 200 DPI.
- Edge-to-edge prints need bleed. With 3 mm on every side, A3 becomes 303 × 426 mm, or 3579 × 5031 pixels at 300 DPI.
- Ready-made A3 frames are common in Europe and often include a mount (mat) cut for A4, which lets you frame an A4 print with a border.
A3 questions
How many pixels is A3 at 300 DPI?
3508 × 4961 pixels. At 200 DPI it is 2339 × 3307, and at 150 DPI 1754 × 2480.
Can I print a phone photo at A3?
Usually, yes. A 12 megapixel phone photo gives about 244 DPI at A3, which looks sharp on a wall. Photos sent through messaging apps are often shrunk, so use the original file.
Is A3 the same as 11 × 17?
No. A3 is 297 × 420 mm (11.69 × 16.54 in). Tabloid is 279 × 432 mm (11 × 17 in). The shapes differ slightly, so expect a small crop when switching between them.
Simple Process
How PrintCheck Works
Three quick steps to ensure your physical prints never come out blurry or pixelated.
Input Target Dimensions
Specify the physical width and height in millimeters (mm) along with your required DPI (300 DPI fine art or custom DPI).
Upload Your Image
Select your image file. We read its pixel size and format, then delete it straight away. Your image is never kept.
Get 3-Tier Results
Instantly view whether your image passes, qualifies for AI upscaling, or requires a higher-resolution file.
Built For Print Shops & Designers
Everything You Need for Quality Control
Exact Pixel Formula
Automates (mm / 25.4) * DPI calculation instantly for any custom physical size.
Privacy-First Processing
Your image is only held while it is being checked, then deleted. We never keep, share or look at your images.
Smart AI Upscale Detection
Detects images that can be saved using modern AI upscaling up to 4× enlargement.
Standard Print Sizes & Pixel Resolution
Reference chart of required pixel dimensions for standard photo, poster, and paper formats.
Pixels = Inches × Target DPI
Example for 8×10" at 300 DPI: (8 × 300) = 2400 px width, (10 × 300) = 3000 px height.
Pixels = (Millimeters ÷ 25.4) × Target DPI
Example for A4 (210×297 mm) at 300 DPI: (210 ÷ 25.4 × 300) = 2480 px, (297 ÷ 25.4 × 300) = 3508 px.
| Print Format | Inches | Metric (mm) | 300 DPI (Gallery Sharp) | 150 DPI (Poster Standard) | Instant Check |
|---|---|---|---|---|---|
| A4 Paper (ISO Standard) | 8.27 × 11.69" | 210.0 × 297.0 mm | 2480 × 3508 px | 1240 × 1754 px | Check A4 |
| A3 Poster (ISO Standard) | 11.69 × 16.54" | 297.0 × 420.0 mm | 3508 × 4961 px | 1754 × 2480 px | Check A3 |
| A5 Booklet (ISO Standard) | 5.83 × 8.27" | 148.0 × 210.0 mm | 1748 × 2480 px | 874 × 1240 px | Check A5 |
| 4x6" Photo (US Photo) | 4.0 × 6.0" | 101.6 × 152.4 mm | 1200 × 1800 px | 600 × 900 px | Check 4×6" |
| 5x7" Photo (US Photo) | 5.0 × 7.0" | 127.0 × 177.8 mm | 1500 × 2100 px | 750 × 1050 px | Check 5×7" |
| 8x10" Print (US Photo & Art) | 8.0 × 10.0" | 203.2 × 254.0 mm | 2400 × 3000 px | 1200 × 1500 px | Check 8×10" |
| 11x14" Print (US Wall Art) | 11.0 × 14.0" | 279.4 × 355.6 mm | 3300 × 4200 px | 1650 × 2100 px | Check 11×14" |
| 12x18" Poster (Posters) | 12.0 × 18.0" | 304.8 × 457.2 mm | 3600 × 5400 px | 1800 × 2700 px | Check 12×18" |
| 18x24" Poster (Posters) | 18.0 × 24.0" | 457.2 × 609.6 mm | 5400 × 7200 px | 2700 × 3600 px | Check 18×24" |
| 24x36" Poster (Posters) | 24.0 × 36.0" | 609.6 × 914.4 mm | 7200 × 10800 px | 3600 × 5400 px | Check 24×36" |
Answers To Common Questions
Frequently Asked Questions
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