Compress PDF to 100 KB or 200 KB Online Free for Email (2026)

Email attachment limits are usually 25 MB, but many recipients have slower connections or corporate filters that reject large files. A 10 MB PDF of scanned documents can be compressed to under 500 KB while remaining readable. FlashKit's PDF compressor now includes target size mode: pick 100 KB, 200 KB, 300 KB, 500 KB, 1 MB, or 2 MB, and the tool adjusts JPEG quality and image downsampling to reach your target.

When to Compress vs. Split a PDF

Compress when the PDF contains embedded photos or scans. These can often be recompressed at lower quality.
Split when the PDF has many pages and the recipient only needs some. Use the Split PDF tool.
Both for a 50-page report with photos: split the pages you need, then compress that subset.

Compress PDF to Target Size

Pick 100 KB, 200 KB, or 500 KB. Runs locally — your PDF never leaves your browser.

Open PDF Compressor

How Target Size Mode Works for PDFs

Open the PDF Compressor.
Switch to "Target Size" mode.
Select a preset: 100 KB, 200 KB, 300 KB, 500 KB, 1 MB, or 2 MB.
In Target Size mode, DPI is chosen automatically (200, 150, 120, 96, then 72, with 60/50 as a last resort). Switch to Quality mode if you want to pick the downsample yourself (200, 150, 96, or 72 DPI).
Optional: Enable "Grayscale" to convert color scans to grayscale.
Drop your PDF and wait for compression.

The tool recompresses embedded JPEG images at progressively lower quality until the target is met, then downsamples if needed. Text-only PDFs don't shrink much — there's nothing to recompress.

Realistic Expectations

PDF Type	Compression Potential
Scanned documents (JPEG inside)	High — often 50–90% reduction
Photos embedded in reports	High — depends on original quality
Text-only PDFs	Low — text is already compact
Vector graphics / charts	Low — vectors don't compress like images
Already-compressed PDFs	None — may even grow slightly

DPI Downsample Explained

A scanned document at 300 DPI contains more pixels than you need for on-screen viewing. Downsampling to 150 DPI halves the pixel count in each dimension (4× fewer total pixels), dramatically reducing file size while keeping text readable. Options:

72 DPI: Smallest files, adequate for screen-only viewing.
96 DPI: Web standard, good for digital documents.
150 DPI: Readable if printed, smaller than original 300 DPI.
200 DPI: Near-print quality, moderate compression.

Compress PDF with DPI Downsample

Reduce scan resolution and file size in one step. No upload required.

Open PDF Compressor

Grayscale for Text Documents

Color scans of text documents waste space. Enable grayscale to convert embedded images to grayscale, typically saving 15–20% with no loss in readability for contracts, forms, and ID copies.

Privacy: PDF Stays Local

FlashKit compresses PDFs in your browser using pdf-lib and the Canvas API. Your document is never uploaded. This is important for contracts, bank statements, and medical records. Close the tab to clear the file from memory.

Merge PDF: Combine multiple PDFs into one before compressing.
Split PDF: Extract only the pages you need.
JPG to PDF: Create a PDF from photos with built-in compression.
PDF to JPG: Export pages as images with target size per page.