Compress PDF to 100 KB

How to compress a PDF to 100 KB

1. Drop the PDF onto the box above, or click it to browse. It is opened here on your device and sent nowhere.
2. Leave Target size on Under 100 KB. If the form quotes a different figure, pick it from the list, or choose Custom and type the number of kilobytes.
3. Leave Compression level on Balanced. With a target set, the level only decides the sharpest resolution tried first; Light starts sharper and may need more attempts.
4. Press Compress PDF. Each attempt redraws the pages and tries several JPEG qualities in one go, keeping the best one that fits. The status line shows the attempt and the resolution in dpi.
5. When the file fits, it downloads with -compressed added to its name. Open it and zoom in before you upload it anywhere.

What people use it for

A 100 KB ceiling usually belongs to a form that expects one small document per upload box, often beside equally strict limits for a photo and a signature — Compress Image deals with those.

• Uploading a birth certificate, ID card or proof of address to an exam or scholarship registration form.
• Attaching the photo page of a passport to a visa or travel-permit application.
• Adding a signed declaration or a one-page CV to a job portal that caps every file.
• Sending a fee receipt or marksheet to a university admission portal.
• Submitting proof of income to a government e-service that rejects larger files outright.

Good to know

Why is a scan so heavy? A colour A4 page scanned at 300 dpi measures about 2,480 by 3,508 pixels — close to nine million — and a phone photo of a document is often bigger still. Getting that under 100 KB means keeping only a small share of the detail, so each page is redrawn as a lighter JPEG. That works well for one or two pages; the more pages there are, the less each one can keep. The text becomes part of the picture, so it can no longer be selected or searched, and links and form fields are lost. The tool never goes below about 58 dpi, because under that small print stops being readable. If even that is too big, it reports the smallest size it reached and how far over the limit that is, and downloads nothing unless you ask.

Websites also disagree about what a kilobyte is: some count 1,000 bytes, others 1,024. To be safe, “under 100 KB” here means 100,000 bytes or fewer, which passes either check. Your passport or certificate is read, redrawn and saved again by this browser tab alone, so there is no uploaded copy for anyone to keep, lose or look at.

Questions people ask

What if it cannot get under 100 KB?

Ask whether the form really needs every page. Removing extras with Delete PDF Pages, or sending the document in parts with Split PDF when there is more than one upload box, usually does it. A fresh scan in greyscale at 150 dpi also gives a far smaller starting point.

How do I know the result is still readable?

Open it at actual size and look at the smallest print that matters: ID numbers, dates, the two machine-readable lines on a passport, stamps and signatures. If any of it has blurred, whoever checks the upload has the same problem, so remove a page and try again rather than sending it.

The portal still says the file is too large. Why?

Some forms apply the limit to all your uploads together rather than to each file, and a few state it in one unit but check it in another. Read the exact wording beside the upload box; if the real limit is lower than it looked, enter it under Custom and compress again.

Is it safe to compress an ID document here?

The file never leaves your device: it is opened and rebuilt by code running in the page. If the original was password-protected, the compressed copy is not, and the page tells you when that happens — keep the copy as carefully as the original.