Merge PDF
Combine PDFs and reorder pages by dragging. Nothing is uploaded.
Resize PDF Pages
Scale or convert pages between A4, Letter and custom sizes.
What it does. A4 and Letter are close but not equal: A4 is taller and narrower, Letter is shorter and wider. Neither fits inside the other, so converting always means either scaling the content slightly or accepting a margin on one axis and a clip on the other.
Runs in your browserNothing uploadsNo signupWorks offline
How to use Resize PDF Pages
- Drop in the PDF and choose the target size.
- Pick scale-to-fit or reposition without scaling.
- Export.
Why A4 and Letter never quite match
| Size | Millimetres | Inches |
|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69 |
| Letter | 216 × 279 | 8.5 × 11 |
| Legal | 216 × 356 | 8.5 × 14 |
| A3 | 297 × 420 | 11.69 × 16.54 |
| A5 | 148 × 210 | 5.83 × 8.27 |
Letter is 6mm wider and 18mm shorter than A4. Print an A4 document on Letter without scaling and the bottom 18mm is cut; scale it to fit and everything shrinks by about 6%, which is usually invisible but does change the effective font size.
Scale or reposition
Scale to fit keeps everything on the page and changes the size of the content. Best for documents that will be read rather than measured.
Reposition without scaling keeps the content at its true size and centres it, accepting margins or a clip. Necessary for anything where dimensions matter — technical drawings, forms with fixed field positions, anything to scale.
The A-series has a useful property here: every A size is exactly half the previous one, with the same 1:√2 aspect ratio. So A4 to A5 or A3 scales perfectly with no distortion, which is not true of any conversion involving Letter.
What resizing does to a form
Interactive form fields have coordinates. Scaling the page without moving them leaves the boxes in the wrong places, which is a common failure when a form is converted between page sizes.
This tool scales field positions along with the content, but the safest route for a form is to keep it at its original size.
If the form is going to be printed and filled by hand, the alignment matters less. If it will be filled digitally or read by a scanner, keep the original geometry.
Frequently asked questions
What is the difference between A4 and Letter?
A4 is 210 × 297mm, Letter is 216 × 279mm — Letter is 6mm wider and 18mm shorter. Neither fits inside the other, so converting means either scaling or accepting a margin and a clip.
Should I scale to fit or reposition?
Scale to fit for documents that will be read. Reposition without scaling when dimensions matter — technical drawings, anything printed to scale, or forms with fixed field positions.
Why does A4 to A5 look perfect but A4 to Letter does not?
Every A size is exactly half the previous one with the same 1:√2 ratio, so A-series conversions scale without distortion. Letter has a different ratio entirely.
What happens to form fields when I resize?
Their coordinates need scaling with the content or the boxes end up misplaced. This tool scales them, but keeping a digital form at its original size is safer.
Is resizing lossless?
Repositioning without scaling is. Scaling changes the transformation applied to the content, which is still vector where the original was vector, so text stays sharp — but the effective font size changes.