How to Compress a PDF Under 100KB Without Losing Quality

Compressing a PDF to meet strict size limits is one of the most common blockers for sending proposals, submitting forms, or uploading to government portals. The goal is to land under 100KB without sacrificing clarity. That means protecting text sharpness, keeping diagrams readable, and reducing image weight with intention?not guesswork.

This guide walks you through a structured, professional workflow to shrink PDFs while maintaining quality. You will learn how to prep files, choose the right compression profile, avoid flattening text, and verify the output so it passes inbox and portal checks the first time.

Use this process for compliance packets, receipts, assignments, or pitch decks. The steps mirror how teams at established SaaS companies ship documents every day: predictable inputs, quick validation, and a repeatable playbook you can save for next time.

Estimated time

Plan for 8?12 minutes: quick cleanup, compression, and a visual QA pass.

Why this matters

Meet strict upload limits for tenders, grants, HR forms, and e-filing portals.
Prevent email bounces by keeping attachments lean and device-friendly.
Protect readability for text, stamps, signatures, and charts after compression.
Work entirely online with Dexify?no installs, drivers, or paid add-ins required.
Standardize a workflow that anyone on your team can follow in minutes.

Step-by-step: compress a PDF under 100KB

Audit the source. Open the PDF and note page count, whether text is selectable, and how many pages contain photos or scans. Selectable text compresses far better than images.
Remove noise. Delete blank pages, redundant covers, and unused appendices. Fewer pages mean faster processing and smaller outputs.
Normalize page size. Keep everything A4 or Letter. Mixed sizes can create larger renders; consistency keeps outputs tight.
Launch Dexify Compress PDF. Open the online tool in your browser?no installation required to start.
Upload your file. Drag and drop the PDF. For large inputs, wait for the upload indicator to finish before selecting settings.
Pick a profile. Start with a balanced or ?smart? profile. Use ?strong? only if the first pass stays above 100KB. Avoid aggressive modes for text-heavy files.
Preserve text and vectors. Ensure the tool keeps fonts embedded and avoids flattening text into images. This retains sharpness and searchability.
Downscale heavy images. For photo-heavy PDFs, aim for ~150 DPI and 70?80% quality. For diagrams or scans, stay closer to 200 DPI to keep labels legible.
Run compression. Click compress and let Dexify process. Server-side steps are secured; where possible, compression happens locally for privacy.
Verify the output. Download the compressed PDF, check size, then review at 150% zoom. Confirm text crispness, signature clarity, and chart labels.
Iterate thoughtfully. Still above 100KB? Trim noncritical pages, convert large color backgrounds to grayscale, or re-run with slightly stronger compression. If quality dipped, revert to balanced and downscale only the heaviest pages.

Mid-process checkpoint

Before you finalize, pause after the first compression pass. Verify the biggest risk areas?stamps, signatures, fine text, and charts. If these remain sharp, you can push a bit harder on images if size demands it. If not, keep the current profile and instead remove optional pages or grayscale background-heavy sections.

Rule of thumb: text should remain text. Avoid workflows that rasterize fonts unless you must lock layout for legal reasons.

Use cases

Education and students

Upload assignments to LMS platforms with size caps. Keep diagrams readable while staying under the limit so submissions never bounce.

Business and sales

Send proposals, case studies, and quotes that open quickly on mobile. Balanced compression prevents fuzzy charts when prospects zoom in.

Legal and compliance

Meet court or e-filing requirements with sub-100KB exhibits while preserving seals, signatures, and page numbering.

Operations and finance

Archive receipts, invoices, and audit packs without ballooning storage. Smaller files also speed up email approvals.

Personal and admin

Compress IDs, forms, and scanned paperwork for online applications without losing critical text clarity.

Tips and best practices

Stay in sRGB. Keep the color profile consistent to avoid unexpected shifts after compression.
Separate concerns. If one page is image-heavy (e.g., a cover), compress that page harder and keep the rest balanced.
Keep originals. Save an uncompressed master so you can re-export at different sizes when requirements change.
Test one page first. For complex diagrams, export a single page to validate clarity before processing the whole file.
Use vector when possible. Charts and logos in vector form stay sharp and compress better than rasterized versions.

Common mistakes to avoid

Flattening text to images. This destroys searchability and often makes text fuzzy. Preserve fonts.
Over-compressing scans. Scanned signatures can become unreadable; keep slightly higher quality on those pages.
Ignoring blank pages. Hidden blanks inflate size; remove them before compression.
Using print-DPI for web. 300 DPI is overkill for most screens. Drop to 150?200 DPI unless you plan to print.

Troubleshooting

Text looks soft: Re-run with text preservation on and a balanced profile. Avoid ?strong? if the document is mostly text.
Images too grainy: Increase image quality to ~80% or bump DPI slightly for charts. Consider keeping key pages at higher quality.
Still above 100KB: Remove nonessential pages, convert heavy color backgrounds to grayscale, or split the document into two smaller PDFs.
Portal rejects the file: Confirm the extension is .pdf, remove passwords if not allowed, and ensure the file is flattened only where necessary.

Conclusion and next steps

Getting under 100KB is about precision, not brute force. Preserve text, trim what you do not need, downscale images thoughtfully, and validate the result at a readable zoom. With Dexify you can do this online in minutes and save a repeatable profile for your next submission.

Keep an uncompressed master on hand, save your preferred compression settings, and combine this flow with Dexify merge or organize tools whenever you build document packets for clients, students, or auditors.

FAQs

Do I need software installed? No. Dexify compresses PDFs in the browser?just upload, choose a profile, and download.
Will text stay searchable? Yes, when fonts remain embedded. Avoid flattening unless absolutely required.
What if my PDF is only scans? Use balanced compression, consider grayscale, and keep DPI around 200 to protect stamps and signatures.
Can I keep under 100KB for long PDFs? For very long files, split into logical sections. For short to mid-length files, the workflow above typically hits the target.
Does compression remove security? No. It targets file size. If your PDF is password protected, you may need to unlock it before compressing depending on policy.