Compress PDF online — free and in your browser

Government portals, university admissions and job applications routinely cap PDFs at 100 KB, 200 KB or 500 KB. Scanned documents from a phone camera are 2–8 MB, so they are rejected long before anyone reads them.

Email attachments bounce above 25 MB, and most Indian bank KYC portals refuse anything above 1–2 MB. Compressing locally means you can retry instantly at a different target size without re-uploading a confidential document to a stranger's server.

Because CompressInKB runs the whole pipeline in your browser tab, documents that legally should not leave your device — salary slips, Aadhaar-linked proofs, medical reports, contracts — never do.

Many application portals place strict size limits on supporting PDFs. Working toward the limit before submitting can save a frustrating failed upload.

Some PDFs contain large photographs or scans; others are mostly selectable text. They respond differently to compression, so compare the output rather than expecting a fixed percentage saving.

The processing engine runs on your device. The application does not upload the PDF to a file-processing server.

This tool exists for PDF documents handled in a hurry: no queue, no account, no upload, and a result you can verify on the spot. The explanation below is the same one we would give a colleague who asked how it works.

Scanned documents behave differently from every other file you have. Each page is a photograph, typically 1–3 MB at 300 dpi in colour, with no text layer unless your scanner ran OCR. That means there is no lossless cleverness available — the bytes genuinely are the picture. The cheapest wins on a scan are usually cropping the grey table edge out of every page and turning off colour where the document is black ink on white paper.

Password-protected and encrypted PDFs are not supported by these tools. If you are authorised to do so, use your PDF reader to make an unlocked copy and try that copy instead. Preserve the original, especially if it has a digital signature.

Accepted inputs are PDF files up to 50 MB. SVG, HTML and other script-bearing formats are refused outright rather than sanitised, because a file that can execute code has no business being re-encoded — and an upload field that accepts one is a security hole rather than a feature. Several files can be queued where the workbench supports it. Batch, page and memory limits apply; check every output.

The structural pass resets common document-info fields and reserialises with object streams. In automatic mode, if the file is still too large, the tool may render pages as images and rebuild the PDF; selectable text and interactive features can be lost. It retains the smaller result it found and reports whether it met the target. XMP and other hidden data may remain. The structural pass rewrites the PDF using object streams and resets common document-info fields. If the chosen mode allows and the result is above target, pages may be rendered to JPEG images and assembled into a new PDF. This loses selectable text and may lose links, forms, accessibility information and other document features. The tool keeps the smaller result it found, which can be the original, and reports when it remains above target. It does not guarantee complete metadata removal or malware sanitisation. A structural rewrite is attempted first. In automatic or rebuild mode the tool may also render pages as JPEG images; that can remove selectable text and interactive features. The card shows the output size and whether the target was met, and the original is kept if the attempts would make it larger.