Compress PDF Online (100% Private)
Shrink a PDF to fit upload limits. Light mode keeps text selectable; Strong mode reaches a target size by converting pages to images.
100% private: your files never leave your browser· 0 requests to other servers since this page opened.How to verify it yourself
In short
CareerPDF compresses PDFs in your browser in two ways: Light mode is lossless and keeps text selectable, while Strong mode reaches a target size such as 500 KB by turning pages into images. Your file is never uploaded.
Job portals, university applications and government forms often reject files over 1 MB, 500 KB or even 200 KB. CareerPDF offers two ways to shrink a PDF, and is honest about the trade-off each one makes.
Light mode is lossless: it removes metadata and rewrites the file structure more compactly, keeping text selectable. Strong mode reaches a size you choose by turning each page into an optimized image, which works on almost any file but makes the text no longer selectable.
Strong mode renders every page only once and prepares five quality levels from that single render, then picks the sharpest level that fits your target. This is much faster than re-rendering the document repeatedly, and it means the result is as good as your size limit allows.
How to compress a PDF in four steps
Step 1: Choose the PDF
Drop the file or pick it with the keyboard. Its current size is shown so you can see how far you need to go.
Step 2: Pick a mode
Start with Light. If the file is still too big, switch to Strong and enter the target size in kilobytes, such as 500 for a common portal limit.
Step 3: Watch the progress
In Strong mode each page is rendered once and encoded at several quality levels. The best level that fits your target is then used. You can cancel at any time.
Step 4: Download and continue
The result shows the size before and after. Download it, or pass it on to the signing or merging tools without choosing the file again.
Zero-Server
Compression without handing over your documents
Most of the files people compress are the ones they are about to submit somewhere: CVs, transcripts, passports, payslips. Cloud compressors must receive the full file to process it, and their privacy policies usually allow keeping it for hours or days.
Here the PDF is rendered by pdf.js and rebuilt by pdf-lib inside your tab. Canvases are capped at a safe size to protect memory on phones, and the pdf.js document is destroyed as soon as compression ends. The only copy of the result is the one saved to your device.
When compression helps
- Getting a CV or portfolio under a job portal’s upload limit.
- Emailing scanned documents without hitting attachment limits.
- Shrinking photo-heavy PDFs before archiving them.
- Preparing application packs for university or visa portals.
Frequently asked questions
How do I compress a PDF to under 500 KB?
Choose Strong mode and set the target to 500. The tool tries five quality levels and uses the best one that fits. If even the lowest cannot reach the target, it tells you.
Should I use Strong mode on my CV?
Avoid it if you can. Strong mode turns pages into images, so an applicant tracking system cannot read the text. Use Light mode, or build a lighter CV with the resume builder.
Why is my file sometimes not smaller in Light mode?
Files that are already well optimized have little metadata or structure to remove. Scans and photo-heavy PDFs usually need Strong mode.
Is my file uploaded to a server?
No. Compression runs entirely in your browser; the file never leaves your device.
Can I compress password-protected PDFs?
No. Encrypted files are detected and rejected. Remove the password first.
Does it work offline?
Yes, once the page and its PDF engine have loaded. After your first use, the app is cached by a service worker, so you can switch off Wi-Fi and keep working. This is also an easy way to prove that nothing is being uploaded.
How large a file can I process?
There is no limit imposed by a server, because no server is involved. The limit is your device’s memory: a modern computer handles files of a few hundred megabytes, while phones are more comfortable below about 100 MB.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox, Safari and Samsung Internet on desktop, Android and iOS. JavaScript must be enabled, because the processing itself is JavaScript running on your device.