How to Edit a Custom Paper Size in AutoCAD
Edit a custom paper size when its dimensions, printable margins, name or source are wrong. Make the change in the same device/PC3 that owns the media definition, then retest the actual sheet.
Start here — what you are going to do
Your goal: Correct one custom paper definition without creating unnecessary duplicates.
Where to start: Identify the exact PC3/device and custom-media name used by the problem Layout.
Beginner rule: Do not create Custom-1, Custom-2 and Custom-3 for every correction. Edit the controlled definition when it is the same media standard.
Step by step — follow this in AutoCAD
Step 1 — Open the owning PC3
Where: PLOTTERMANAGER > double-click PC3.
Do this: Open Device and Document Settings.
Check: Correct configuration is open.
Step 2 — Open Custom Paper Sizes
Where: User-Defined Paper Sizes & Calibration > Custom Paper Sizes.
Do this: Select the media.
Check: Correct size is highlighted.
Step 3 — Click Edit
Where: Custom Paper Sizes > Edit.
Do this: Open the wizard.
Check: Current settings are visible.
Step 4 — Correct the definition
Where: Wizard pages.
Do this: Change only needed size/margin/name/source.
Check: Definition matches physical sheet.
Step 5 — Finish and save
Where: Wizard > Finish > OK.
Do this: Save PC3/PMP changes.
Check: Edit persists.
Step 6 — Reopen Page Setup
Where: PAGESETUP > Paper Size.
Do this: Confirm updated media.
Check: Layout sees it.
Step 7 — Preview and test
Where: Preview > PDF/plotter.
Do this: Verify border and scale.
Check: Original problem is solved.
Beginner example
A 24 × 60 roll definition clips the bottom border. Edit its printable area rather than creating another 24 × 60 size with a confusing name.
Understand what AutoCAD is doing
Custom media belongs to the output configuration
Editing the wrong PC3 will not fix another device.
Printable area can change without sheet dimensions
Useful when nominal paper is correct but margins are not.
Changes can affect many Layouts
Treat shared media edits as standards changes.
Useful next guides: Custom Paper Sizes: Complete Guide · Add a Custom Paper Size to an AutoCAD PC3 · AutoCAD Printable Area and Plot Margins Explained · AutoCAD Border Cut Off When Plotting · PMP Files
Common problems and what to check first
| What you see | What may be causing it | Check this first |
|---|---|---|
| Edit unavailable | Windows system printer | Use manufacturer Custom Properties. |
| Layout still old | Another media/PC3 selected | Check Page Setup. |
| Other sheets change | They share the edited media | Verify project-wide impact. |
| Settings vanish | Standards sync overwrote local file | Update controlled master. |
When you need a more repeatable workflow
Version controlled PC3/PMP files are important when custom media are shared. Record old/new margins for regression testing.
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
Can I change only margins?
Yes in supported workflows.
Should I rename after a margin fix?
Usually keep the controlled media identity if it remains the same standard.
What should I test?
A border test and one scale-critical output.
Explore more in CAD Paper Sizes, Margins & Printable Area.