Exact 20 kB target · Free · No upload
Compress PDF to 20kB
Lands a small PDF at or just under 20 kB, the tightest budget we offer — built for single-page signature and declaration scans, with an honest message when a file cannot fit.
Files never leave your device — compression runs in your browser.
Drop your PDF here
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PDF · up to 100 MB · any number of pages
- No upload
- 100% free
- Any device
Processing on your device — large PDFs can take a minute.
Need a photo at this size instead? Compress an image to 20 kB .
Step by step
How to compress PDF to 20kB?
Works on phones, tablets and computers — no account needed.
- 1
Upload the PDF
Drop your PDF into the box above or click to browse. Scanned documents, forms, certificates and multi-page reports all work. The file stays on your device.
- 2
Confirm the target size
The target is pre-set to 20 kB here. You can change the number, switch the unit to MB or a percentage, and tick black & white for scanned pages that do not need colour.
- 3
Compress and download
We try a lossless clean-up first and only re-render pages when the file is still too big. Compare the first page before and after, then press Download.
Where this size shows up
Where a 20 kB PDF is typically required
Twenty kilobytes is the smallest PDF preset on Mb2KbSizer, and it is a genuinely tight budget: a whole page has to fit in less space than a typical phone screenshot. People who need to compress a PDF to 20 kB are almost always dealing with one page rather than a document — a scanned signature, a handwritten declaration, an undertaking, a fee acknowledgement — because that is all that fits with the writing still readable. Before you start, check what the form really asks for. Recent SSC notices and the IBPS scanning guidelines put the signature at 10–20 kB, but as a JPG, not a PDF; for those fields, compress the image to 20 kB instead.
Where PDFs meet the number 20, it is usually as the lower edge of a window rather than the cap. UPSC's online application FAQ accepts a photo ID or PwBD certificate as a PDF of 20–300 kB, so a file that lands at 19.6 kB would sit under the floor; for that portal pick 50 kB or more. The NTA bulletins for NEET UG 2026 and JEE Main 2026 want certificates as PDFs of 50–300 kB, where 20 kB is simply too small. This preset is the right choice only when the field states a ceiling at or below 20 kB, or when there is no minimum and you want the lightest possible file for a weak connection.
What fits in 20 kB with our PDF compressor: one page of typed text in black & white, a signature strip, a short digital receipt with no pictures. What does not: colour scans, photographs, and anything beyond two or three pages, since every page draws from the same 20 kB. When a document is bigger than that, the tool says so and suggests a larger target, black & white, or splitting the file, rather than handing you something unreadable. The 50 kB and 100 kB presets are one click away for exactly that case.
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Signature page requested as a PDF
Some application systems accept the signature only as a PDF attachment. Scan just the strip you signed, tick black & white, and 20 kB is enough for clean strokes.
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Handwritten declaration or undertaking
A few lines in black ink on white paper compress well: the page is mostly empty, so the whole budget goes to the writing itself.
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Fee receipt or acknowledgement slip
Payment confirmations exported from a portal are small text PDFs. If there are no logos or embedded fonts, the lossless pass can fit them under 20 kB with the text still selectable.
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A short proof to send on a weak connection
A 20 kB PDF goes through in a few seconds even on a patchy mobile signal, which matters when a portal times out on bigger attachments.
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Form fields with a ceiling below 50 kB
A few college, scholarship and municipal portals cap every attachment at a few tens of kilobytes. If a field states 20 kB for a PDF, this preset lands just under it.
Reference
Portals with PDF limits around 20 kB
Typical limits from official notifications and help pages. Each row links to its source.
| Portal / purpose | Item | Size limit | Format | Source |
|---|---|---|---|---|
| UPSC Online (OTR / application FAQ) | Photo ID proof or PwBD certificate Read on the official FAQ on 2026-10-14. 20 kB is the minimum of this window, not the cap; a file just under 20 kB is too small, so target 50 kB or more for UPSC. | 20–300 kB | Official | |
| NEET (UG) 2026 – NTA information bulletin | Category, Class X, marksheet, address or PwD certificate Per the 2026 bulletin; 20 kB is below the minimum, so use 50 kB or above. Check the current bulletin before uploading. | 50–300 kB | Official | |
| JEE (Main) 2026 – NTA information bulletin | Class 10 certificate or ID proof Per the bulletin for the 2026 exam; a 20 kB PDF would fail the minimum. Always check the latest notification. | 50–300 kB | PDF (JPG: 10–200 kB) | Official |
Limits change between recruitment cycles. Always confirm the numbers on the notification or form you are filling in before you upload.
Pro tips
Tips to reach 20 kB without losing readability
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Upload one page, not the whole file
Every page draws from the same 20 kB. One page gets the full budget; three pages get under 7 kB each, which is enough for bold headings and little else. If the portal wants only the signed page or the declaration, make a PDF of that page alone before you compress it.
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Tick black & white before you press compress
At 20 kB there is no room for colour. Grayscale leaves one channel of brightness instead of three, so the remaining bytes go into edges: the strokes of a signature, the letters of a typed line. For an ink-on-paper scan this one tick is frequently the difference between fitting and not fitting.
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Scan the strip, not the sheet
A signature or a two-line declaration does not need an A4 page around it. Crop the scan or photo to the written area before saving it as a PDF, so the page itself is small and every pixel the tool keeps is useful. A clean white background costs almost nothing; shadows and creases are expensive.
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Do not expect embedded fonts to fit
A one-page PDF exported from Word or Google Docs carries subsets of every font it uses, and those alone are frequently larger than 20 kB. The lossless method cannot shrink font data much, so at this target the tool will normally re-render the page as an image. That is fine for a declaration; it is not fine if the portal needs searchable text.
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Scan at low resolution and high contrast
The re-render runs at up to 150 dpi and goes lower only when it must, which at 20 kB it will. A grey, low-contrast scan forces the tool to spend bytes on noise, while a crisp black-on-white scan at 100–150 dpi compresses into far fewer. If your scanner app has a document or black & white mode, switch it on before you export.
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Check the preview before you upload
The result card shows the first page before and after. Zoom into the signature strokes or the smallest text. If they break into blocks, raise the target to 50 kB where the form allows it, or re-scan in black & white with a smaller page. A 19 kB file nobody can read will be rejected just as surely as a 30 kB one.
Quality check
What to expect at 20 kB
A one-page scan almost never fits through the lossless pass: the page is already a photograph inside the PDF, usually several hundred kilobytes, and re-saving the file structure cannot shrink the picture. So the tool re-renders it. At 150 dpi an A4 page is about 1240 × 1750 pixels, far more than 20 kB can hold as a JPEG, so the passes step the resolution down until the budget works and the page ends up noticeably smaller in pixels than the scan you started with. Typed text at 11 or 12 points stays legible, a signature keeps its shape, and faint pencil or 8-point footnotes may not survive. With black & white ticked the same bytes buy visibly cleaner edges.
A three-page signed form gets under 7 kB per page. That is workable for a black-and-white typed form where most of each sheet is empty, though tick boxes and small print will soften; a colour scan or a form with a pasted photograph will not fit. The tool makes up to three passes before it stops, and if 20 kB is out of reach it tells you so and suggests a larger target, black & white, or splitting the file into the pages that are actually needed. Text is not selectable after re-rendering, and form fields and links are gone.
A ten-page report is not a 20 kB document. Two kilobytes per page is less than a readable JPEG page takes at any resolution the tool would use, so re-rendering cannot get there; the only way through is the lossless pass, which realistically works only for a tiny digital PDF with no images and no embedded fonts. Expect the message that the target cannot be met, and move to 100 kB or more. Whatever route runs, a successful result lands a little under 20 kB, never over, which is what a strict upload check wants to see.
Good to know
Frequently Asked Questions
Will text stay readable in a PDF compressed to 20 kB?
For a single page of typed text, yes, as long as you tick black & white. The page is re-rendered as a JPEG at reduced resolution, so letters look slightly soft when you zoom in but read normally at page width. Signatures and headings keep their shape. Very small print, light grey text and anything in colour are the first things to degrade; if the document depends on them, choose a bigger target.
Can a multi-page PDF fit into 20 kB?
Two pages of black-and-white typed text, sometimes three. Beyond that, each page's share of the budget is too small for a readable image, and the tool will report that 20 kB cannot be reached. Digital PDFs are the exception only when they are tiny to begin with; most carry embedded fonts that outweigh the whole target. Split the file and upload only the required pages, or use 50 kB.
Why is the result 18 or 19 kB instead of exactly 20 kB?
The tool aims at or just under the target and keeps a result that fits rather than one that nudges over, counting 1 kB as 1,000 bytes. Landing a few hundred bytes short is deliberate: portals that count 1,024-byte kilobytes would otherwise see a file over their limit.
One caution at this size: where 20 kB is the minimum of a window, such as UPSC's 20–300 kB for PDF certificates, a 19 kB file is too small, so aim higher there.
My form says the signature must be 10–20 kB. Do I need a PDF?
Usually not. The 10–20 kB signature limit in recent SSC notices and in the IBPS and SBI scanning guidelines refers to a JPG, with IBPS asking for about 140 × 60 pixels. A PDF will not be accepted in a field that lists only JPG/JPEG. Use compress image to 20 kB, which also lets you set exact pixel dimensions, and reach for this PDF preset only when the field explicitly accepts PDF.
What should I do if the tool says 20 kB cannot be reached?
Three things, in order. Tick black & white and run it again; for scans that alone often closes the gap. Then cut the file down to the page the portal actually asked for and save it as its own PDF. If it still will not fit, the document genuinely needs more room: pick 50 kB or set a custom target on the PDF compressor, and double-check whether the limit really is 20 kB for a PDF — it is often a JPG limit for a different field.
What is Mb2KbSizer and what does it do?
Mb2KbSizer shrinks images and PDF documents to a size you choose, free of charge, without leaving your browser. Give the PDF compressor a file of up to 100 MB, enter a target in kB, MB or as a percentage of the original, and it works to bring the document under that figure. Typical jobs include getting a scanned marksheet below a portal's cap, squeezing a multi-page application form into an email, or lightening a report before sharing it. The same site offers an [image compressor](/) and a bulk image compressor, both built on the same no-upload approach.
Is Mb2KbSizer free to use?
It is, with no catches. You will not meet a paywall after the first file, a cap on pages, a size restriction beyond the 100 MB input limit, or a stamp on the output. We do not ask for an email address or an account. Ads on the page cover our hosting bill, and since your device does the processing, we have no per-file costs to pass on. Whether you compress one certificate or every document for a job application, the price is the same: nothing. There is no paid plan waiting behind the free one.
Do I need to install any app to use Mb2KbSizer?
There is nothing to install. The PDF compressor is a normal web page that loads its compression code (Mozilla's pdf.js and pdf-lib) into the browser and runs it there. Any current version of Chrome, Edge, Firefox, Safari or Samsung Internet will do, on Android, iPhone, Windows, macOS or Linux. You can pin the page to your home screen through your browser's Add to Home Screen option if you like a one-tap icon, but it still fetches the page over the internet each time, so it is not an offline app. We publish nothing in any app store, and no software needs updating.
How do I compress a PDF using Mb2KbSizer?
Start by dropping your PDF into the upload box or tapping browse to select it; the tool opens the file on your device. Next, check the Target Size field. On a preset page the number is already filled in, but you can change it and switch the unit between kB, MB and %. Tick black & white if the file is a scan and you want extra savings. Then press the compress button. The result panel shows the first page before and after, the new size, the percentage saved, the page count and which method was used. Press Download to save the file.
What formats does Mb2KbSizer support?
This tool accepts PDF files only, up to 100 MB and with any number of pages. It cannot open a password-protected PDF; remove the password in the program that created it, then try again. Word, Excel or image files need converting to PDF first, which most phones and computers can do through Print to PDF or Save as PDF. The output is always a standard PDF with the original page sizes. If you want to shrink photos rather than documents, use the [image compressor](/), which handles JPG, PNG, WebP, GIF, BMP, AVIF and HEIC where the browser can decode it.
Is it safe to upload my PDFs to Mb2KbSizer?
Your PDF is never sent anywhere, so there is no upload to worry about. The browser opens the file locally, and both compression methods run on your own processor: the lossless pass re-saves the document with compressed streams, and the re-render pass draws each page and packs it into a fresh PDF, all in memory on your device. Our servers only deliver the page itself. This matters for the kind of documents people compress: ID scans, bank statements, offer letters, medical reports. They remain as private after compression as they were before you opened the tool.
Do you store my PDFs?
We cannot store what we never receive. Because the whole process happens in your browser, no copy of your document, its pages or its text is written to our servers, and there is no account history tying files to you. The compressed PDF lands in your Downloads folder and nowhere else. Our hosting provider keeps standard server logs for page requests, which record things like IP address and browser type but never file contents. We also run no database. For a plain-language description of what little data the site does handle, see our privacy policy.
Sources & further reading
- UPSC online application FAQ – photo, signature and PDF document limits (upsconline.gov.in)
- NEET (UG) 2026 Information Bulletin – upload specifications (NTA)
- JEE (Main) 2026 Information Bulletin – upload specifications (NTA)
- SSC CGL 2026 notice – signature upload specification (ssc.gov.in)
- IBPS CRP PO/MT-XV – guidelines for scanning and upload of documents
Have a photo to shrink too?
Our image compressor lands JPG, PNG and WebP files at an exact kB size — handy when the same form needs a photo and a PDF.