What are the dimensions of A3 paper?

297 x 420 mm or 11.69 x 16.54 inches.

What pixel dimension do I need for A3 at 300 DPI?

You need a file resolution of at least 3508x4960 pixels to print at 300 DPI cleanly.

How does ResizeFlow automate this process?

Upload your master design. ResizeFlow automatically generates all standard aspect ratios at 300 DPI in a single ZIP package.

A3 Paper Dimensions Size Guide: mm & Inches Table

Quick Answer

A3 paper dimensions are 297 x 420 millimeters (11.7 x 16.5 inches). In printable wall art, A3 is a standard small poster size in the ISO paper ratio family. A high-resolution A3 file can be scaled down to print A4 and A5 prints. ResizeFlow automates this setup by automatically upscaling and formatting a single design file into A3 sizes at 300 DPI in seconds.

Understanding the A3 Format

A3 paper is twice the size of A4 and is commonly used for office brochures, small posters, visual flyers, and home wall art.

To ensure your shop covers all common aspect ratios, review our list of sizes in the 2:3 printable size guide.

A3 Dimensions and Pixel Requirements

To print A3 layouts cleanly, use these dimensional conversions:

Millimeters: 297 x 420 mm
Inches: 11.69 x 16.54 inches
Pixels at 300 DPI: 3508 x 4960 pixels

Preparing A3 Printables with ResizeFlow

Designing at large dimensions ensures quality downscaling but requires robust file preparation. ResizeFlow automates this workflow.

Upload your design, select your target aspect ratios, and choose either the Scale to Fit (Preserve Entire Artwork) or Smart Center Crop modes. ResizeFlow upscales each file to 300 DPI and compiles them in structured ZIP folders.

A3 Paper Dimensions Size Guide