Reduce a PDF to 100 KB and keep it readable

Get under the limit in five steps

Use Resize PDF. You pick the limit, and it makes the sharpest version of your PDF that fits under it, right in your browser:

1. Open Resize PDF and leave "What to change" on File size.
2. Pick the portal's limit under "Make it under": 50 KB, 100 KB, 200 KB, 500 KB, 1 MB or 2 MB. For anything else, like 300 KB, pick Other, type the number and press Enter.
3. Choose your PDF. The resizer tries a few settings, showing "Try 1", "Try 2" as it goes. Most scans take a few seconds.
4. Read the result line (explained just below).
5. Download and upload. The new file's name ends in the size you picked, like marksheet-100KB.pdf, so you can tell it from the original.

Picked the wrong size? Just pick another one. Files you already added are done again at the new size straight away.

What the result tells you

Under 100 KB

It fits. This is the file to upload.

Over 100 KB

It couldn't get that small, and you are looking at the smallest version possible. See when it won't fit.

Pictures: Sharp, Good, Readable or Rough

How sharp the scanned pages stayed. Readable is typical for a scan at 100 KB. Rough means you should check the small print carefully.

Already under 100 KB

Your original fits as it is. Upload it unchanged.

How the size target works

Nobody can tell in advance how small a PDF will get at a given setting, so the resizer doesn't guess. It makes the file, measures it, adjusts and tries again, closing in until a version lands just under your limit, within 15% of it. In our tests that took 2 to 5 tries. The size finder section of the guide describes each step.

Three things are worth knowing about how it decides:

• Only pictures change. Text, fonts, lines and drawings are copied as they are, so typed words stay sharp and searchable at any size. Scanned pages are pictures, so they are what gets smaller.
• The limit is a budget shared by every page. 100 KB for a 4-page scan is about 25 KB a page. For a 6-page scan it is about 17 KB a page. More pages means less detail for each one.
• 1 KB means 1,000 bytes here. Some websites count 1 KB as 1,024 bytes. Because we count the smaller way, a file under 100 KB here is under 100 KB on every website, so there is no need to pick a lower size "to be safe".

Why not just use the compressor's Smallest level? A level can't aim at a number. Smallest keeps pictures at up to 100 pixels per inch, but to fit under 100 KB, our test scans had to go down to between 48 and 73. Resize PDF goes as low as the limit needs, and no lower. With no number to meet, as for email, the compressor is the better tool.

Real results for 100 KB, 200 KB, 500 KB and more

We resized these files in Google Chrome on our test computer. "Pictures" is the word the result showed, with the pixels per inch the scan kept where we measured it.

What these results teach:

• All three scans we tried at 100 KB fit, though they started at 6 to 10 MB, and all stayed Readable.
• Page count matters. Our 4-page sample kept 73 ppi under 100 KB, while the 6-page colour scan had to go to 48. Part of that is the shared budget: each extra page leaves less room for the rest.
• A bigger limit buys sharpness fast. The same sample went from Readable at 100 KB to Good at 500 KB. If the portal allows more, use it.
• Long text-heavy files have a floor. The textbook stopped at 2.56 MB, because its text and drawings were kept as they are. For a file like that, fewer pages is the only way down.

How readable is a 100 KB PDF?

Readable, for normal text. In our tests, normal-sized text in a scan could still be read at 48 ppi, though it looked soft, and read easily at 57 ppi. The person checking your application on a computer screen can read it. What suffers first is the fine detail:

• Small print: roll numbers, registration numbers, dates of birth and the fine print under tables.
• Stamps and seals, especially faint ones, and signatures in light blue ink.
• Photos on ID cards and admit cards. Faces become small and soft.
• Security patterns and coloured backgrounds on certificates, which can turn blotchy.

How to check: open the new file on your phone and zoom in until the page is about as big as the real paper. Read every number the portal might need. If you can read them, so can the reviewer. If you can't, try a bigger limit if the portal allows one, or make the scan easier to shrink (next section).

Typed PDFs are different. If your PDF was made on a computer, like a downloaded certificate or a resume saved from Word, its text is real text and stays perfectly sharp at any size. Only its pictures, such as a logo or a photo, lose detail.

The sharpness table in the guide shows which pixels per inch each result word stands for.

When the file won't fit, or comes out Rough

If the result says Over, or says Rough and you can't read the small print, the file has too much to fit in the budget. Work through these, starting with the easiest:

1. Send fewer pages. Blank back pages from two-sided scanning, an instructions page, a second copy of the same certificate: each one you remove gives the rest more room. Delete pages with Organize PDF, or keep only the ones you need with Split PDF.
2. Use separate uploads if the portal has them. If there is one slot for the Class 10 marksheet and another for Class 12, each file gets its own limit. Split PDF can save each page as its own PDF.
3. Scan again in grayscale. A grayscale scan has no colour to store, so more of the limit goes to sharpness. Our tools can't turn a colour scan grey for you, but scanners have a grayscale setting, and most scanner apps have a grayscale or black-and-white filter.
4. Scan again at a sensible setting. 150 to 200 dpi is plenty for a form upload. Lay the page flat, in good light, and crop to the paper's edges: shadows, grain and the table around the page all take room the words could use.
5. Start from the original. A copy that was already made smaller has lost detail for good. Go back to your first scan for every new limit.
6. Don't scan typed documents. If you have the original file, like a resume in Word, save it as PDF directly. A typed page saved straight to PDF often needs only a few kilobytes.

If the file is mostly text and still says Over, its text and fonts set its smallest size: our 117-page textbook stopped at 2.56 MB. Fewer pages is what helps. The guide's section on this explains why.

Tips for exam, job and government portals

• Read the exact rule. Portals often say more than the size: "PDF only", "single file", "A4", "colour scan", or a range like "50 KB to 300 KB". Note it all before you start.
• For a range, aim at the top. If the rule is "between 50 KB and 300 KB", pick 300 KB. The resizer lands just under your size, within 15% of it, so a big scan comes out well above the minimum. A file already under 300 KB is kept as it is.
• Expect your phone to show a slightly different number. File apps count kilobytes in different ways, so a 98 KB file might show as 96 KB in one app. The portal's own check is the one that counts, and our counting fits all of them.
• Several papers, one upload? Merge them in the order asked with Merge PDF first, then resize the merged file, because the limit applies to the file you upload.
• A4 and a size limit? Change the page size first, then the file size, so the limit is checked on the file you upload. Changing a PDF to A4 explains how.
• Photo and signature uploads are often JPG, not PDF. They usually have their own size and pixel rules. Resize PDF works on PDFs only. If a portal wants a page of your PDF as a JPG, PDF to JPG can make one: at its Small setting, the pages of our sample scan were 60 to 70 KB each.
• Use plain file names. Some portals reject names with spaces or symbols. A name like marksheet_class12.pdf is safe.
• Upload the right copy. Pick the file ending in your size, like -100KB.pdf, not the original scan with a similar name.
• Don't leave it to the last day. Portals can get slow near the last date. Prepare your files a few days early and keep the originals in one folder for the next form.

Doing it all on a phone

Many people fill in these forms on a phone, and the whole job works there, from paper to upload, with no app to install for the resizing:

1. Scan the paper with a document scanner, like the one in Google Drive on Android or in the Files app on iPhone. Choose grayscale for black-and-white papers, and save as PDF.
2. Open Resize PDF in Chrome, Safari or Samsung Internet, pick the limit and choose the scan from where the scanner saved it.
3. Download the result. On Android it goes to Downloads; on iPhone it usually goes to Downloads in the Files app.
4. Open the portal in another tab, tap its upload button, choose to pick a file rather than a photo, and select the file ending in your size.

It is light on your device, too. In our tests on a computer, scans up to 10 MB took 1 to 5 seconds, and resizing the 6.37 MB scan needed 65 MB of memory, handed back as soon as it finished. A phone may take a little longer. Once the page has loaded, it keeps working without internet, which helps where the signal is weak.

Aadhaar, PAN and marksheets stay with you

The documents portals ask for are the most private ones you own: Aadhaar and PAN cards, marksheets, caste and income certificates, bank statements. Most online resizers upload them to their servers to do the work. Resize PDF doesn't: it runs inside your browser, and the new file is saved straight to your phone or computer. The only place your document goes is the portal you choose to upload it to.

You can check this yourself: once the page has loaded, turn off Wi-Fi and mobile data and resize a file. It still works, because nothing needs to be sent. There is no sign-up and no watermark, and the privacy section of the guide says more about how it is protected.