Open the app — PDF Left-Right Splitter
Open a scanned classical text from a library and more often than not it was photographed with the book lying open.
Two pages on one sheet.
On paper that feels natural, but on a screen or a tablet the characters end up half size.
The page numbers are half the real count too, so every citation needs arithmetic.
This tool cuts such PDFs down the middle and separates them into single pages.
It sounds simple, but in practice plenty of things get in the way.
The cover is a single sheet yet gets sliced in half, vertically written books must be read right to left, and characters near the binding get cut off.
Each of those has its own setting here.
How to Use
Basic Steps
- Drag a PDF file in or click to upload it.
- Adjust the options you need.
- Click [Split PDF].
- The split PDF downloads automatically.
Leaving the Covers Alone
Turn on Exclude front cover or Exclude back cover and those pages are kept whole instead of being cut.
Covers are usually scanned as a single sheet, so cutting them leaves you with half a cover.
Check the first and last sheets of the file you received before deciding.
Excluding Specific Pages
If a foldout or a full-bleed plate sits in the middle, list its number.
Those pages stay intact.
3-5, 10 → pages 3, 4, 5, and 10 are not cut
Ranges and individual numbers can be mixed.
Page Order
This decides which half comes first — and it matters more than you’d think.
| Setting | For which book | Result |
|---|---|---|
| Right → Left | Vertically written classics, Korean-bound texts | The right page comes first |
| Left → Right | Horizontally written modern books | The left page comes first |
Classical Chinese texts read from right to left.
On an open spread, the right page is the earlier one.
Choose wrong and every page lands out of order, so always confirm with the preview.
Split Overlap Ratio
Cutting at the exact center sometimes shaves off characters near the binding.
Scanning an open book curves the inner margin, pulling the text toward the middle.
| Value | How it cuts |
|---|---|
| 0 | Exactly at the center |
| 0.1 – 0.5 | Overlapping the center by that much |
With overlap, a sliver of the same area appears on both halves.
The reasoning is simple: a little duplication beats losing characters.
Start at 0.1 and raise it while watching the preview.
Preview
Once the file is loaded you can see the result before cutting.
- Blue marks the left page, red marks the right page.
- Use ◀◀ ◀ ▶ ▶▶ to move through pages.
Discovering the order is wrong after cutting hundreds of pages means starting over.
Flipping through a few pages at the beginning, middle, and end catches most mistakes.
Good to Know
Rotated Files Are Handled for You
Scanners sometimes store pages on their side.
The page looks upright on screen, but the rotation value inside the PDF says 90 or 270 degrees.
Split such a file naively and it gets cut top to bottom, because the coordinate system is turned.
So the rotation value (0, 90, 180, 270) is read for each page and the cut direction is adjusted to match what you see.
On a page rotated 90 degrees the cut runs vertically in the original coordinates, and the lower part becomes the visual left half.
At 270 degrees it’s the other way around.
In short, what you see in the preview is what gets saved. You don’t need to think about rotation at all.
Notes
- Large files may take a long time or fail, since everything is processed in browser memory.
- All processing happens in the browser and no file is sent to a server. Unpublished material is safe here.
Open the app — PDF Left-Right Splitter