12x18" Poster Quality Checker
A 12 × 18 inch (305 × 457 mm) poster requires 3600 × 5400 pixels at 300 DPI (or 1800 × 2700 px at 150 DPI).
At 300 DPI (Gallery Sharp): Minimum 3600 × 5400 pixels.
At 150 DPI (Poster Viewing): Minimum 1800 × 2700 pixels.
12×18" Print Guide
Everything you need to print 12x18" Poster sharp
The 12 × 18 inch print (30 × 46 cm) is a small poster and photo enlargement size. It has the same 2:3 shape as 4 × 6 and 24 × 36, and the same shape as most camera sensors, so camera photos print uncropped.
At 300 DPI it needs 3600 × 5400 pixels, about 19.4 megapixels. A 24 megapixel camera (6000 × 4000) reaches about 333 DPI, so most interchangeable-lens camera photos print sharp at this size.
Phone photos need cropping from 4:3 to 2:3, and a 12 megapixel phone photo then gives about 224 DPI: still good on a wall. AI art at 1024 × 1536 needs about 2.8× upscaling to reach 240 DPI.
12×18" at a glance
| Size | 304.8 × 457.2 mm · 30.48 × 45.72 cm · 12 × 18 in |
|---|---|
| Shape (aspect ratio) | 2 : 3 |
| Common uses | Concert posters, anime art prints, digital art merchandise. |
Pixels needed for 12×18"
| Resolution | Pixels (width × height) | Megapixels | Best for |
|---|---|---|---|
| 300 DPI | 3600 × 5400 | 19.4 MP | Close up (photos, cards, documents) |
| 240 DPI | 2880 × 4320 | 12.4 MP | Framed and wall prints |
| 150 DPI | 1800 × 2700 | 4.9 MP | Posters viewed from a distance |
Pixel sizes are for portrait. For landscape, swap width and height.
Tips for printing at 12×18"
- Same shape, different size. A 2:3 file made for 24 × 36 also prints perfectly at 12 × 18; one made for 4 × 6 has the right shape but only reaches 100 DPI.
- For posters on a wall, 200–240 DPI (2400 × 3600 to 2880 × 4320 pixels) is usually indistinguishable from 300.
- Poster paper choice matters: matte hides minor softness better than gloss.
12×18" questions
How many pixels is 12 × 18 at 300 DPI?
3600 × 5400 pixels. At 240 DPI it is 2880 × 4320, and at 150 DPI 1800 × 2700.
Can I enlarge a 4 × 6 print file to 12 × 18?
The shape is identical, but a 1200 × 1800 file is only 100 DPI at 12 × 18 and will look soft. Start from the original photo or upscale it 2–3× first.
Will my camera photos fit 12 × 18 without cropping?
Most will. DSLR and mirrorless cameras shoot 2:3, the same shape as 12 × 18.
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
Print Guides
Learn how to get sharp prints
How to Check an Image’s Resolution on Windows, Mac, iPhone and Android
Step-by-step for every device, which number to look at, and which one to ignore.
How to Print AI Art Sharp: Sizes, Upscaling and Common Problems
How far a 1024 px image goes, the upscale factor for popular sizes, and what to fix before printing.
Print-on-Demand Image Requirements: A Guide for Gelato, Printful and Printify Sellers
Resolution, templates, transparency and colour: how to prepare designs that print well on shirts, mugs and wall art.
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