How to Scan Documents to a PDF Under 200KB on Your Phone
Your phone is a decent scanner. The trouble is the file it makes. A three page scan can easily come out at 5MB or more, while the form you are filling in accepts only 200KB.
You can get there in two steps. First, scan in a way that keeps the file small from the start. Second, compress the result to the exact size you need.
This guide covers both, on iPhone and Android, using free tools you already have. We also share what we learned from our own size tests, so you know which settings actually matter.
The quick method
- Scan the page with Notes or Files on iPhone, or Google Drive on Android.
- Use a black and white or greyscale filter for plain text pages.
- Save it as a PDF.
- Open our PDF compressor, pick 200KB, and add the scan.
- Download the result and upload it to your form.
The rest of this article explains each step and the small habits that keep scans sharp at a tiny size.
Why phone scans come out so big
A scan is a photo of your page. It stores every pixel, including paper texture, shadows and camera noise. Typed text inside a normal PDF costs almost nothing, but a picture of that same text costs a lot.
We built test scans of one A4 text page to see where the size comes from:
| One A4 page | Size |
|---|---|
| Colour scan, 300 DPI | 1,507 KB |
| Colour scan, 150 DPI | 541 KB |
| Greyscale scan, 150 DPI | 523 KB |
| Black and white scan, 150 DPI | 73 KB |
| Black and white scan, 200 DPI | 117 KB |
Two lessons stand out. Resolution matters a lot. And true black and white is far smaller than colour, while plain greyscale saves surprisingly little on its own. You can read the full breakdown in our guide on why a PDF gets so large.
How to scan on iPhone
Apple builds a document scanner into the Notes and Files apps. The Files route is quicker because it saves a PDF straight to a folder.
- Open the Files app.
- Tap the More button (three dots), then Scan Documents.
- Hold the phone over the page. In Auto mode it captures by itself. You can also press the shutter or a volume button.
- Drag the corners if the crop is off, then tap Keep Scan.
- Add more pages if needed, then tap Done.
- Choose a folder and tap Save.
On iOS 26 you can choose an image filter before you capture. Apple’s scanning guide covers both Notes and Files. For text documents, pick a filter that makes the page black and white or grey and the background clean.
How to scan on Android
Most Android phones have Google Drive installed, and it includes a good scanner.
- Open the Google Drive app.
- Tap the Camera button at the bottom right.
- Point the camera at the page and capture it. A blue outline shows the crop area.
- Tap Filter and choose a greyscale or black and white style for text pages.
- Use Clean to erase marks or fingers at the edges.
- Tap Done, name the file and choose .pdf as the format.
- Tap Save.
Google’s help page for Drive scanning lists every option. Files by Google also has a scanner that saves PDFs into a Scanned folder inside Downloads, which is handy if you do not use Drive. Note that Drive saves your scan to your Google account, so use Files by Google if you would rather keep it only on the phone.
Six habits for a small, sharp scan
1. Use even, bright light
Shadows and dim light add grey tones that the file has to store. Scan near a window in daylight or under a bright ceiling light. Turn off the flash if it creates a glare spot.
2. Put the page on a dark, plain surface
A dark table helps the app find the edges and crop tightly. A tight crop means fewer wasted pixels around the page.
3. Do not get too close
Filling the screen with the page captures it at the camera’s full resolution. Holding the phone a little further back still gives readable text, with a smaller file. Some iPhone users report much smaller scans after stepping back slightly while the app still crops automatically.
4. Pick the right filter
For typed or printed text, black and white gives the smallest file. Use colour only when colour carries meaning, such as a coloured stamp, a photo ID or a signature in blue ink.
5. Scan only what the form needs
Every extra page eats into your 200KB. If the form asks for the first page of a certificate, scan only that page.
6. Keep the page flat and straight
A curled or tilted page creates gradients and odd shadows. Press it flat, and let the app straighten the corners.
Compress the scan to under 200KB
Even a careful scan often lands between 300KB and 2MB. This is the step that gets you under the limit.
- Open our PDF compressor in Chrome or Safari.
- Tap 200KB, or choose Custom and type 190 for a safe margin.
- Add your scan from Files, Downloads or Drive.
- Wait a few seconds, then tap Download.
The tool lowers image resolution and quality only as much as your target needs, so the result stays as clear as the size allows. It runs inside your browser, so your scan is never uploaded.
In our tests, a 2.48MB phone scan came down to 172KB, and a 10.02MB scan reached 191KB.
If you need the step by step version for both phones, see our guide on how to compress a PDF on your phone for online forms.
How many pages fit in 200KB
The more pages you scan, the less room each page gets. Here is a rough budget that works well for text documents:
| Pages | Space per page | Best setting |
|---|---|---|
| 1 | about 190 KB | Colour or greyscale is fine |
| 2 | about 95 KB | Greyscale, compressed |
| 3 to 4 | 45 to 60 KB | Black and white recommended |
| 5 to 8 | 24 to 38 KB | Black and white, tight crop |
Past eight pages, text may become hard to read at 200KB. Check whether the form allows separate uploads, or whether it accepts a larger file. Our document upload size guide lists the real limits for the most common Indian portals.
Already took photos instead of scanning?
No problem. If your pages are photos in your gallery, use our JPG to PDF tool. Add the photos in order, choose 200KB, and it builds one PDF that fits the limit. It resizes each photo to the page, which removes most of the extra size straight away.
If the form wants an image instead of a PDF, use our image compressor on the photo directly.
Check it before you upload
- Open the PDF and zoom in. Make sure names, dates and numbers are readable.
- Check the size. On iPhone, touch and hold the file in Files and tap Get Info. On Android, open file details in the Files app.
- Check the page order if you scanned more than one page.
- Rename the file to something short like certificate.pdf if the portal is fussy about names.
FAQ
How do I scan a document to PDF under 200KB on my phone?
Scan the page with Notes or Files on iPhone, or Google Drive on Android, and save it as a PDF. Then open our PDF compressor in your browser, choose 200KB and add the scan. Download the result and check its size before uploading.
Which filter makes the smallest scan?
Black and white makes the smallest file for text pages. In our tests a black and white page at 150 DPI was about 73KB, while the same page in colour was about 541KB. Greyscale on its own saved very little.
What DPI should I use to scan for online forms?
150 DPI is enough for most typed documents and keeps the file small. Use 200 DPI if the text is very small. Phone scanner apps do not usually show a DPI setting, so compressing to your target size afterwards does the same job.
Can I scan a document to PDF without an app?
On iPhone, yes. Notes and Files are built in. On Android, Google Drive or Files by Google come preinstalled on most phones. Samsung and Pixel cameras can also detect documents. You do not need a separate scanner app.
Why is my iPhone scan so large?
Recent iPhones capture scans at high resolution, so a few pages can reach several megabytes. Stepping back slightly while scanning, choosing a black and white filter and compressing the PDF afterwards all bring the size down.
Will compressing my scan make it blurry?
It can soften fine detail at very small sizes, especially with many pages. Good light, a clean filter and scanning only the pages you need keep the text clear. Aim for a target close to the form’s limit rather than far below it.
