How do I merge multiple PDFs into one without uploading them?

Open PDF Studio and drop two or more PDFs onto the canvas, or click Open to add them. Pick Merge from the toolbar, drag the thumbnails to set the page order, then click Save. The merge runs entirely in your browser using pdf-lib via WebAssembly — your files are never uploaded. You can merge up to 20 PDFs at once, and the combined output keeps the original page sizes, orientations, and embedded fonts intact.

How do I split a PDF into separate files?

Open the PDF and pick Split from the toolbar. Choose a mode: split by range ("pages 1-3, 7, 10-end"), split every N pages, or extract each page as a separate file. PDF Studio produces a ZIP containing every output PDF and downloads it with one click. The whole operation runs locally in your browser, so even confidential documents stay on your device.

How do I compress a PDF in the browser?

Open the PDF and pick Compress from the toolbar. Choose a quality preset — Low (smallest size, lossy image recompression), Recommended (balanced for sharing), or High (preserve quality, modest savings). The compressor downsamples embedded images, removes duplicate fonts and unused objects, and re-encodes streams. Most invoices, scans, and reports compress 40-70 % without visible quality loss. Everything happens client-side, so a 90 MB scan does not need to be uploaded to a third-party service.

How small can I make a PDF before quality suffers?

It depends on what is inside. Text-only PDFs compress very little (the source is already small). Scanned PDFs and PDFs with high-resolution embedded photos shrink dramatically — often 60-80 % at the Recommended preset, more at Low. Diagrams and vector graphics compress less because vector data is already compact. The compress dialog shows the projected output size before you save, so you can pick the preset that fits your target.

How do I rotate pages in a PDF?

Open the PDF and pick Rotate from the toolbar. The page thumbnails appear with rotation handles — click 90° clockwise or counterclockwise on a single page, on a selected range, or on all pages at once. Rotations are written into the PDF's page tree, so the rotated orientation persists in every viewer (Acrobat, Preview, browsers, mobile readers). The operation is fast even on documents with hundreds of pages because it changes metadata, not pixels.

How do I reorder pages in a PDF?

Open the PDF and pick Reorder from the toolbar. Drag the page thumbnails to a new position; multi-select with Ctrl/Cmd or Shift to move groups; right-click to delete a page outright. The new order is written into the saved PDF. The reorder tool is also useful for splitting one document into several — drag pages out into separate groups, then save each group as its own file.

How do I password-protect a PDF online?

Open the PDF and pick Protect from the toolbar. Enter a user password (required to open the document) and optionally an owner password (required to remove restrictions like printing or copying). Save the document; the encryption is applied to the saved copy and the original is left untouched. PDF Studio uses the AES-128 encryption supported by every modern PDF reader. Because protection is applied locally, your password is never transmitted anywhere.

What encryption does the password protection use?

PDF Studio uses AES-128 PDF encryption, which is supported by every modern PDF reader (Acrobat, Preview, browser viewers, and most mobile apps). It is strong enough for ordinary file sharing — guessing a 12-character password would take longer than the age of the universe at current hardware speeds. Pick a passphrase rather than a short password for any document you care about.

How do I remove a password from a PDF without uploading it?

Open the protected PDF and pick Unlock from the toolbar. Enter the password you already know and click Unlock; PDF Studio decrypts the document in the browser using the supplied password and lets you save an unprotected copy. Because the entire operation happens locally, your password is never sent anywhere. PDF Studio cannot unlock documents you do not have the password to — that would require breaking the encryption, which is not what this tool does.

What if I don't know the password to a protected PDF?

PDF Studio cannot unlock a document without the correct password — that would require brute-forcing AES encryption, which is computationally infeasible for any non-trivial password. If the document came from your employer or a service, contact the owner. If you set the password yourself and forgot it, your password manager or browser may have remembered it. We will not add password-cracking features because that is what bad actors look for, and it would compromise the trust model of every legitimate user.

How do I add a watermark to a PDF?

Open the PDF and pick Watermark from the toolbar. Choose text or image; for text, enter the string and pick a font, size, color, opacity, rotation, and tile mode (single, repeated diagonally, or per-page header/footer). For images, drop a PNG or JPG and choose its position and opacity. Apply the watermark to all pages or to a selected range. The watermark is rendered into the saved PDF and visible in every viewer.

Can I add an image watermark to a PDF instead of text?

Yes. In Watermark, switch the mode from Text to Image and drop a PNG or JPG. The image watermark accepts opacity (0-100 %), position (9 anchor points or custom), size (percentage of page width), and rotation. PNG transparency is preserved so logos with cutouts blend cleanly. The watermark image stays in the browser and is composited into the PDF locally — your logo is never uploaded.

How do I extract text from a scanned PDF using OCR?

Open a scanned or image-based PDF and pick OCR from the toolbar. Choose the language (over 30 languages including English, French, Spanish, German, Arabic, Chinese, Japanese, Korean) and click Run. OCR uses Tesseract.js v6 in WebAssembly to recognize text page by page; progress is shown live. The result is a searchable, copy-pastable text PDF — same pages, but with a hidden text layer behind the images. Quality depends on scan resolution: 200-300 DPI usually gives reliable results.

Which languages does the PDF OCR support?

PDF Studio's OCR uses Tesseract.js v6 and supports 30+ languages including English, French, Spanish, German, Italian, Portuguese, Dutch, Polish, Russian, Arabic, Hebrew, Chinese (simplified and traditional), Japanese, Korean, Hindi, and more. Each language pack downloads on-demand the first time you select it (5-10 MB each), then is cached for subsequent runs. Right-to-left scripts (Arabic, Hebrew) and CJK scripts are recognized with the same accuracy as Latin scripts.

How do I convert images to a single PDF?

Open the Image to PDF tool from the toolbar and drop one or more images (JPG, PNG, WebP, HEIC). Drag thumbnails to set the order, choose page size (auto, A4, US Letter, custom), orientation, and margin, then click Save. The resulting PDF contains every image on its own page at the chosen size. The conversion runs in the browser, so even sensitive scans of receipts or IDs stay on your device.

How do I convert a PDF to JPG or PNG images?

Open the PDF and pick PDF to Image from the toolbar. Choose JPG (smaller, lossy) or PNG (lossless, transparent backgrounds preserved), the resolution (72-600 DPI), and the page range. PDF Studio renders each page using PDF.js, exports the chosen format, and packages multiple pages as a ZIP. This is useful for embedding pages in slides or websites, sharing a single page on social media, or extracting figures from a research paper.

Can I extract specific pages from a PDF as images?

Yes. In the PDF to Image tool, the page range field accepts ranges like "1-5, 7, 10-end" or "1, 3, 5". Pick only the pages you need and pick a format (JPG, PNG) and resolution. The output is a ZIP containing one image per requested page. This is how to grab a single chart from a long report or share a specific certificate page without revealing the rest of the document.

How do I edit text, shapes, images, or signatures I added to a PDF?

Click any item you placed on the page to select it. A small floating toolbar appears with a Trash icon (delete) and — for text — a Pencil icon (edit content). The font, size, and colour bar at the top of the page also follows the selected text, so you can change style on the fly. To resize an image, signature, or shape, drag any of the eight handles around its bounding box; hold Shift while dragging a corner to preserve aspect ratio. Drag the body of the item to move it. Click anywhere outside the editing UI (or press Enter when an inline editor is open) to save. Press Escape to discard a text change.

How do I delete a text, shape, image, or signature I added by mistake?

Click the item to select it, then click the Trash icon in the small floating toolbar that appears next to it. The Delete and Backspace keys do the same when the item is selected and you are not typing in another input. Removal is instant and tracked in the studio's history, so undo (Ctrl/Cmd+Z) brings the item back if you change your mind. The original PDF stream is not modified until you save.

Can I change the font, size, or colour of text I already placed?

Yes. Click the text on the page; the Text style bar at the top of the viewport reflects that text's current font, size, and colour. Adjust any of them and the change applies to the selected text in real time — you do not need to switch tools. The same selected-style behaviour works for shapes via the Shape style bar (colour, opacity). Clicking somewhere outside the editing UI commits the change.

How do I resize an image, signature, or shape I added to the PDF?

Click the item to select it. Eight square handles appear on the corners and edges of its bounding box. Drag any handle to resize from that side. Hold Shift while dragging a corner to keep the original aspect ratio (useful for photos and signatures so they do not stretch). Freehand-drawn shapes scale their points proportionally with the bounding box. Text items are not resized via handles — use the size selector in the Text style bar instead.

Is my PDF uploaded to a server?

No. PDF Studio runs every tool — merge, split, compress, rotate, reorder, protect, unlock, watermark, OCR, image-to-PDF, PDF-to-image — entirely in your browser using WebAssembly libraries (pdf-lib, PDF.js, Tesseract.js, Ghostscript-WASM). Your file is loaded into memory once, processed locally, and saved back to your disk. No upload, no temporary cloud copy, no telemetry. You can verify this in DevTools → Network: the only requests during processing are for the WASM binaries themselves (loaded once and cached).

What's the maximum PDF size I can edit?

PDF Studio handles files up to 100 MB without breaking a sweat on a modern laptop. Above that, performance depends on your machine — phones may struggle on PDFs over 50 MB, while desktops with 16 GB of RAM can comfortably edit 200 MB documents. Compress and OCR are the most memory-hungry operations because they touch every page; merge and split are nearly instant regardless of size.

Can I edit a password-protected PDF?

Not directly — encryption hides the document from every editing tool, including PDF Studio. First, use the Unlock tool with the correct password to produce an unprotected working copy, then edit it with any other tool, and finally re-apply protection with the Protect tool when you save. The unlock-edit-relock cycle stays entirely in your browser; the password and content never leave your device.

Does PDF Studio work offline?

Once the page has loaded and the WebAssembly binaries are cached (after one online use), PDF Studio works offline for every operation it does locally — merge, split, rotate, reorder, watermark, image-to-PDF, PDF-to-image, password protect/unlock. Offline OCR requires the language pack to have been previously downloaded. The first visit needs network to fetch the page and WASM modules; after that, you can use it on a plane, in a tunnel, or behind a firewall with no connectivity.

What happens to my PDF after I close the tab?

It is gone. PDF Studio holds your file only in browser memory while the tab is open. There is no IndexedDB persistence, no LocalStorage of file content, no service-worker copy, no analytics event with the file payload, no temporary upload. Closing the tab releases the memory and the document is irrecoverable from PDF Studio. This is the same model as a desktop editor that does not save automatically — and it is the only model that lets us promise privacy without asking you to trust us.

Can I use PDF Studio on mobile?

Yes. PDF Studio works in mobile Chrome, Safari, Firefox, and Edge on Android and iOS. The toolbar adapts to the smaller screen and the canvas supports touch gestures for page reorder, zoom, and selection. Memory is the main constraint — phones can run out of RAM on PDFs over 50 MB. For occasional merges, splits, and watermarks of regular documents, mobile works as well as desktop.

How does PDF Studio compare to iLovePDF or Smallpdf?

iLovePDF and Smallpdf upload your file to their servers, process it there, and return the result. They have larger feature sets (AI summarization, e-signature, OCR for images), but you must trust their servers with your document. PDF Studio runs every operation in the browser via WebAssembly — no upload, no account, no daily-merge limits, no server retention. The tradeoffs: a few advanced features (AI summarization, server-side OCR for very large scans) live there, not here.

Does PDF Studio leave any trace on my computer?

Only the cached WebAssembly binaries and your browser's normal cache (favicons, fonts, the page itself). The PDF you edit is held in RAM and discarded when you close the tab. No file is written to disk other than what you explicitly download via Save. If you use Incognito/Private mode, the WASM cache is cleared on tab close too.

Can I use PDF Studio in my company's secure environment?

Yes — that is exactly the use case. Because nothing is uploaded, the document never crosses your firewall and you do not need to vet a third-party data processor for GDPR, HIPAA, or internal compliance. The site itself is loaded over HTTPS and the WASM binaries are versioned and cached. A blocklist for cloud upload tools does not block PDF Studio because there is nothing to upload.

Why does the first PDF operation take a few seconds to start?

The first time you use a tool, the matching WebAssembly binary is downloaded — pdf-lib (~150 KB), PDF.js (~400 KB), Tesseract.js (~10 MB plus language packs), or Ghostscript (~6 MB for compress). After that, the binaries are cached by the browser and the tool starts instantly on subsequent runs. We split the binaries by tool so you only pay the load cost for what you use.

Can I cancel a long PDF operation?

Yes. Compress on a 90 MB scan or OCR on a 200-page document can take a few minutes; the toolbar shows a Cancel button while a tool is running. Cancelling stops the worker thread and discards any partial output — the original PDF is untouched.

Can I open and edit multiple PDFs in the same session?

Yes. PDF Studio supports a multi-tab workspace — each open document gets its own canvas with independent zoom, page order, and undo/redo. Switch between PDFs without losing in-progress edits. This is useful for cross-document workflows like comparing two reports, copying pages from one to another via Reorder + Merge, or batching the same watermark across several files.

What PDF features does PDF Studio support?

Standard PDF 1.4-2.0 documents: text, vector graphics, embedded raster images, fonts (TrueType, OpenType, Type 1, Type 3), transparency, annotations, form fields, AES-128 encryption, bookmarks, and hyperlinks. Operations preserve embedded fonts and images. Tagged PDFs (used for accessibility) are preserved through merge, split, rotate, and reorder. PDF/A archival format is preserved structurally but not validated.

PDF Studio Online Free - The all-in-one privacy-first PDF workspace

How It Works

Open or Drop

Drop a PDF onto the canvas or click Open to load one from your computer. PDF Studio accepts files up to 100 MB and handles every operation locally — your file is loaded directly in the browser via WebAssembly and is never sent to a server.

Pick a Tool

Use the toolbar to choose what you want to do — merge, split, compress, rotate, reorder pages, password-protect, unlock, watermark, run OCR, convert images to PDF, or convert PDF pages to images. Each tool surfaces only the controls it needs, so the workspace stays uncluttered.

Edit and Preview

Page thumbnails update live as you reorder, rotate, or remove pages. Add text, shapes, images, and signatures directly on the page; click any placed item to select it, drag the corner handles to resize, drag the body to move, click the pencil to rewrite text, or hit the trash icon to delete. Tools like compress and watermark show the result before you commit, and every operation is undoable. Chain several tools on the same document without re-uploading.

Save

Download the result as a PDF (or as images, depending on the tool). The browser prompts for a filename and saves to your disk. The original PDF never leaves your device, and no copy is kept once you close the tab.

Tools inside PDF Studio

Merge PDF

Combine multiple PDFs into a single document. Drag thumbnails to reorder before saving.

Split PDF

Split by page range, every N pages, or extract each page as a separate file.

Compress PDF

Reduce PDF size with Low / Recommended / High quality presets. Most documents shrink 40-70 %.

Rotate PDF

Rotate one page, a range, or every page 90° clockwise or counterclockwise. Persists in every viewer.

Reorder Pages

Drag page thumbnails to a new position, multi-select to move groups, right-click to delete.

Password Protect PDF

Add AES-128 encryption with a user password and optional owner password.

Unlock PDF

Remove a known password from a PDF. Cannot break encryption — you must know the password.

Watermark PDF

Add a text or image watermark with control over position, opacity, rotation, and per-page selection.

PDF OCR

Extract text from scanned PDFs in 30+ languages using Tesseract.js — output is a searchable PDF.

Images to PDF

Combine JPG, PNG, WebP, or HEIC images into one PDF. Drag thumbnails to set the order.

PDF to Images

Convert PDF pages to JPG or PNG at any resolution. Pick a page range and download as a ZIP.

Frequently Asked Questions

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