How to Set A3 Paper Size in AutoCAD
A3 is 297 × 420 mm. In AutoCAD, select the real printer or PDF device first, then choose A3 from that device's Paper Size list and make sure the Layout title block matches the physical sheet.
Start here — what you are going to do
Your goal: Configure one Layout to output on A3 (297 × 420 mm) without scaling the sheet itself.
Where to start: Open the production Layout designed for A3.
Beginner rule: The Paper Size list belongs to the selected output device. If the size is missing, check the printer/PC3 before changing the drawing.
Step by step — follow this in AutoCAD
Step 1 — Open the correct Layout
Where: Bottom tabs > production Layout.
Do this: Use the sheet intended for A3.
Check: The title block is visible.
Step 2 — Open Page Setup Manager
Where: Output > Plot > Page Setup Manager > Modify.
Do this: Open the Layout’s named setup.
Check: Output controls are visible.
Step 3 — Choose the output device
Where: Printer/Plotter > Name.
Do this: Select the approved PDF PC3 or physical plotter.
Check: The device media list refreshes.
Step 4 — Select A3
Where: Paper Size list.
Do this: Choose the entry whose dimensions match 297 × 420 mm.
Check: Paper matches the title block.
Step 5 — Set orientation
Where: Drawing Orientation.
Do this: Match portrait/landscape to the Layout.
Check: The sheet is correctly oriented.
Step 6 — Keep Layout full size
Where: Plot Area = Layout / Plot Scale.
Do this: Use normal 1:1 Layout output.
Check: No extra scaling exists.
Step 7 — Preview
Where: Ctrl+P > Preview.
Do this: Check border and printable area.
Check: The A3 sheet is ready.
Beginner example
A3 is commonly used for details, reduced sets and small plans. If the Layout was designed for A3, a missing A3 option is a device/media problem—not a reason to resize the title block or use Fit to Paper.
Understand what AutoCAD is doing
A3 as a CAD working size
A3 is widely used for details, office review sets and reduced technical drawings. Because A3 is also a common desktop-printer size, confirm whether the PDF is a true A3 production Layout or a reduced copy of a larger sheet.
The device controls the available paper list
AutoCAD shows media exposed by the selected printer, plotter or PC3.
The dashed boundary is the printable area
The nominal sheet is larger than the region some devices can mark.
The Layout normally remains 1:1
Viewport scales control model views; Paper Size controls the real sheet.
Useful next guides: ISO A-Series Paper Sizes for CAD: A0 to A4 · CAD Paper Sizes Explained: ISO, ANSI and ARCH · AutoCAD Printable Area and Plot Margins Explained · AutoCAD Border Cut Off When Plotting · Landscape vs Portrait and Plot Rotation
Common problems and what to check first
| What you see | What may be causing it | Check this first |
|---|---|---|
| A3 is missing | Selected device does not expose it | Check device/PC3/driver. |
| Border is clipped | Title block exceeds printable area | Check margins. |
| Sheet rotates | Orientation/media variant differs | Use Preview. |
| Paper print is smaller than PDF | Viewer applies Fit/Shrink | Use Actual Size. |
When you need a more repeatable workflow
Keep a named Page Setup for recurring A3 output and test it on every approved PDF/plotter device used by the team.
Official Autodesk references
AutoCAD labels and available media can vary by release, driver and output device. These Autodesk pages document the core workflow used in this guide.
Frequently asked questions
What are the dimensions of A3?
297 × 420 mm.
What is A3 commonly used for?
Details, reduced sets and small plans.
Why can the size be missing?
Because the selected output device controls the Paper Size list.
Explore more in CAD Paper Sizes, Margins & Printable Area.