A4 Size in Pixels, CM, and Inches
A4 paper size is 210 × 297 mm, 21 × 29.7 cm, or 8.27 × 11.69 inches. At 300 DPI, an A4 print needs 2480 × 3508 pixels. US Letter is 8.5 × 11 inches and needs 2550 × 3300 pixels at 300 DPI.
A4 Size in Pixels: Width × Height by DPI
A4 measures 210 × 297 mm (21 × 29.7 cm). Its pixel dimensions depend on resolution: at 300 DPI, use 2480 × 3508 px in portrait or 3508 × 2480 px in landscape.
| DPI | Portrait (px) | Landscape (px) |
|---|---|---|
| 72 | 595 × 842 | 842 × 595 |
| 96 | 794 × 1123 | 1123 × 794 |
| 150 | 1240 × 1754 | 1754 × 1240 |
| 200 | 1654 × 2339 | 2339 × 1654 |
| 300 | 2480 × 3508 | 3508 × 2480 |
| 600 | 4961 × 7016 | 7016 × 4961 |
Formula: pixels = millimeters ÷ 25.4 × DPI. Swap width and height for landscape.
300 DPI is a common starting point for photos and detailed artwork viewed up close. Changing the DPI number alone does not add image detail. These values cover the full sheet; printer margins reduce the printable area.
Need a print larger than one A4 sheet? Follow the Mac guide to printing an image across multiple A4 pages.
In This Guide
- A4 Size in Pixels at Different DPI
- What Size is A4 Paper?
- A4 Size in CM, Inches, and Pixels
- A4 vs US Letter Size
- US Letter Size in Inches and Pixels
- Quick Answers
- What DPI Should You Use for A4 Printing?
- How Large Can You Print on A4 Paper?
- How to Print Large Posters on A4 Paper
- Printing PDFs on A4 Paper
- Common Questions
- Summary
What Size is A4 Paper?
A4 paper size is 210 × 297 mm (21 × 29.7 cm or 8.27 × 11.69 inches).
It is the standard paper size used in most countries outside North America.
A4 Size in CM, Inches, and Pixels
If you are checking paper measurements first, the key values are simple:
- A4 size in cm: 21 × 29.7 cm
- A4 size in inches: 8.27 × 11.69 inches
- A4 size in mm: 210 × 297 mm
To prepare a full A4 image in a design or photo editor, set the canvas to 210 × 297 mm and choose the resolution you need. For 300 pixels per inch, the corresponding raster size is approximately 2480 × 3508 pixels. Keep the same proportions when resizing so the artwork does not stretch.
A4 vs US Letter Size
US Letter is the standard office paper size in the United States and Canada. It is close to A4, but the two sizes are not interchangeable when scale, margins, or edge placement matter.
| Paper | Dimensions | Practical difference |
|---|---|---|
| A4 | 210 × 297 mm 8.27 × 11.69 in | Narrower and 17.6 mm (0.69 in) taller than Letter |
| US Letter | 215.9 × 279.4 mm 8.5 × 11 in | 5.9 mm (0.23 in) wider and shorter than A4 |
For US printers: Select Letter when 8.5 × 11 inch paper is loaded. This keeps the page grid, physical print size, and Auto Margin calculation matched to the real paper and printer.
If a PDF or sewing pattern was designed for A4, print it at 100% only on A4 paper when exact physical scale matters. Printing the same file on Letter can clip content or change its scale. For posters where the exact finished dimensions are flexible, Letter works well as long as Letter is selected in both PrintTiler and the macOS print dialog.
US Letter Size in Inches and Pixels
US Letter paper is 8.5 × 11 inches, or 215.9 × 279.4 mm. It is the standard office paper size in the United States and Canada. The required pixel dimensions depend on the print resolution.
| DPI | Pixels | Typical use |
|---|---|---|
| 300 DPI | 2550 × 3300 pixels | Photos, detailed artwork, and sharp text viewed up close |
| 200 DPI | 1700 × 2200 pixels | Good detail with a more manageable source file |
| 150 DPI | 1275 × 1650 pixels | Posters and classroom materials viewed from farther away |
| 96 DPI | 816 × 1056 pixels | Screen-oriented layouts and low-resolution drafts |
| 72 DPI | 612 × 792 pixels | Screen display rather than final print output |
Before printing: Select the paper that is physically loaded in the printer. A4 and Letter are close in size, but choosing the wrong one can change the tiled grid, margins, and final physical dimensions.
Quick Answers
- What size is A4? -> 210 × 297 mm
- Is 150 DPI enough? -> Yes for posters, 300 DPI for photos
- A4 in pixels at 300 DPI? -> 2480 × 3508 px
- US Letter in pixels at 300 DPI? -> 2550 × 3300 px
What DPI Should You Use for A4 Printing?
The right DPI depends on how the print will be used.
300 DPI
Best quality
Best for photos and detailed prints viewed up close. This is the safest choice when you want clean text, sharp edges, and fine image detail on A4 paper.
Use when: Printing photos, illustrations, or anything people will inspect at arm's length.
150 DPI
Good poster quality
Good for posters or large prints viewed from a distance. It reduces file size and print time while still looking solid for wall display.
Use when: Printing posters, classroom materials, or reference prints that are not meant for close inspection.
72 DPI
Preview or draft
Useful for screen previews and low-detail drafts. At A4 size, photos printed at this resolution usually look soft or visibly pixelated.
Use when: You are exporting for on-screen preview rather than physical print output.
For most poster printing, 150-300 DPI is recommended. If you want a deeper explanation of how print quality changes with resolution, see our DPI and resolution settings guide.
How Large Can You Print on A4 Paper?
A4 paper is relatively small, but you can print larger images by splitting them across multiple pages.
Typical tiled poster workflow
- A poster can be printed across 4, 6, or even 9 A4 pages
- Each page prints one portion of the image
- The pages are then assembled into a larger final print
This method is often called tiled printing or poster printing.
How to Print Large Posters on A4 Paper
To print a large image across multiple A4 pages:
- Choose your target poster size.
- Split the image into multiple pages.
- Print each page at the correct scale.
- Assemble the pages together.
See our full guide onhow to print a large poster on A4 paper.
Print a large image across A4 pages with PrintTiler
Printing PDFs on A4 Paper
Large PDF files can also be printed across multiple A4 pages.
This is especially useful for:
- Blueprints
- Maps
- Technical documents
Learnhow to print large PDF files across multiple A4 pages.
Common Questions
How many pixels is A4?
A4 has no single pixel size: it depends on resolution. In portrait orientation, A4 is 2480 × 3508 pixels at 300 DPI, 1240 × 1754 at 150 DPI, or 794 × 1123 at 96 DPI. Its physical size stays 210 × 297 mm.
What is A4 size in pixels at 300 DPI?
Use 2480 × 3508 pixels for a portrait A4 image at 300 DPI. For landscape A4, use 3508 × 2480 pixels. These dimensions cover the full sheet before printer margins.
What is A4 size in cm and inches?
A4 measures 21 × 29.7 cm, or approximately 8.27 × 11.69 inches. In landscape orientation, the width and height are reversed.
Is A4 the same as 8.5 × 11 inch paper?
No. 8.5 × 11 inches is US Letter. A4 is 210 × 297 mm; Letter is 215.9 × 279.4 mm. Select the size actually loaded in your printer to avoid unintended scaling or clipping.
Is 150 DPI enough for an A4 print?
150 DPI can work for posters viewed from a distance. For photos, small text, or artwork viewed up close, start with 300 DPI and check the source image detail. At A4 size these settings require 1240 × 1754 and 2480 × 3508 pixels respectively.
Does changing an image to 300 DPI make it sharper?
Changing DPI metadata alone changes how existing pixels map to physical size; it does not add detail. Check both the pixel dimensions and the intended print size. Enlarging an image beyond its available detail can still produce a soft print.
Summary
Understanding A4 size, its difference from US Letter, and the required DPI is essential for getting predictable print results.
If you want to print large images or PDFs across multiple A4 pages, tools like PrintTiler can help you split and align pages accurately.
