How to Compress a PDF to 100 KB, 200 KB or 1 MB
Neither Preview on a Mac nor Windows can aim a PDF at a size such as 100 KB. File Acture's Compress PDF can: set Compress by to Target size, type 100 KB, 200 KB or 1 MB, and it finds the best image quality that fits, on your own computer. If the PDF can't get that small, it tells you the smallest size it can reach.
Updated September 25, 20264 min read
By the File Acture team
Job portals, university applications, government forms and banks often cap uploads at 100 KB, 200 KB, 500 KB or 1 MB. A phone scan of a single page is usually several megabytes, so the file has to shrink by ten times or more without becoming unreadable.
What fits in 100 KB, 200 KB, 500 KB or 1 MB?
Text takes little space: a PDF of typed pages usually fits in 100 KB unless it embeds large fonts or pictures. The size comes from images, which in most application documents means scanned pages and photos.
As a rough guide, one scanned A4 or Letter page at 150 DPI fits in 100–200 KB, sharper in grayscale than in color. Three to five scanned pages fit in 500 KB, and around ten pages in 1 MB. Photos of documents taken with a phone are larger than scans until they are compressed.
Can a Mac or Windows compress a PDF to a set size?
Not to a set size. On a Mac, Preview's File > Export has a Reduce File Size filter, but it is one fixed recipe: a large scan may still be too big and a small one comes out blurry. See why Preview makes PDFs blurry.
Windows has no PDF compressor of its own. Printing to Microsoft Print to PDF doesn't shrink a scanned document, and often makes it larger; see why Print to PDF files are so big. Online compressors offer levels such as low, medium and strong, and you try again until one fits.
How to compress a PDF to exactly 100 KB
In File Acture's Compress PDF, set Compress by to Target size, type 100 and choose KB. The app tries image resolutions and JPEG qualities, measures the real file size and corrects itself, so the result lands at or just below 100 KB. Text and vector graphics are not touched.
File Acture counts in decimal units, like Finder and most portals: 100 KB is 100,000 bytes, so a file under that limit also passes a site that counts a kilobyte as 1,024 bytes. Each copy gets “-compressed” in its name and the original stays as it was.
Several files, several limits
Add all your documents at once; each one is compressed to the same target. Need different limits for different forms? Run the tool again with the next size. The steps are the same on a Mac (Compress PDF on Mac) and on Windows (Compress PDF on Windows).
What if the PDF won’t fit in 100 KB?
File Acture tells you the smallest size it can reach. Then one of these usually helps:
- Grayscale: turn on Convert images to grayscale; a document rarely needs color and the file gets much smaller.
- Fewer pages: send only the pages the form asks for; Split PDF extracts them.
- Rescan: a scan at 150 DPI in grayscale starts much smaller than a 600 DPI color scan.
- Check the rules: some portals accept several files or a larger limit for some documents; see PDF size limits on application portals.
Is it safe to compress an ID or payslip online?
Online compressors upload the document, which matters for passports, diplomas, bank statements and payslips. File Acture compresses on your computer and never uploads the file.
The free version includes 3 runs on each device, with up to 5 PDFs per run. See pricing for Pro.
How to compress a PDF to 100 KB with File Acture
- 1
Open Compress PDF
Choose Compress PDF and drag in your PDFs, or click Choose Files….
- 2
Choose Target size
Under Size, set Compress by to Target size.
- 3
Enter the limit
Type 100, 200 or 500 and choose KB, or type 1 and choose MB.
- 4
Compress
Click Compress. The bar at the bottom shows each file’s size before and after.
Compress PDFs to 100 KB, 200 KB or 1 MB, without uploading.
Free to try · runs on your device
| Limit | A typed document | Scanned pages, 150 DPI | Tip |
|---|---|---|---|
| 100 KB | Usually | About 1 | Grayscale helps most |
| 200 KB | Usually | 1–2 | Grayscale for 2 pages |
| 500 KB | Yes | 3–5 | Color is usually fine |
| 1 MB | Yes | About 10 | Split longer scans |
Questions
How do I compress a PDF to 100 KB?
In File Acture, set Compress by to Target size, type 100 KB and click Compress. The result lands at or just under 100 KB.
Why can’t my PDF get under 100 KB?
It has too many scanned pages or photos for that size. Turn on grayscale, send fewer pages or rescan at 150 DPI.
Is 100 KB the same as 0.1 MB?
Yes, in the decimal units File Acture and most sites use. Aim a little under the limit if a site is strict.
Does it work on Windows too?
Yes. File Acture has the same Compress PDF tool on Mac and Windows.
Will the text still be readable?
Yes. Only images are compressed; text and vector graphics stay sharp at any size.