How to compress a PDF to an exact size (MB) — free, no signup

You don't need a smaller PDF. You need one under a specific number — 25 MB for a Gmail attachment, 10 MB for a job-application portal, 5 MB for a client's upload form, 2 MB because some government site from 2009 says so. "Make it smaller" isn't the task. "Get it under X" is.

That's the gap in almost every compressor: they give you presets — Low / Medium / High, or "Basic / Strong" — and leave you to guess. You pick Medium, get 7.3 MB, still over the 6 MB limit, try High, now it's a blurry 4 MB, and you've uploaded your document to a random website twice to find out.

This is a short guide to compressing a PDF to a size you choose, exactly — for free, with no account.

The fastest way: set the target, get the file

1. Open the free compressor: sourceback.app → PDF → Compress to size.
2. Upload your PDF and type the target — e.g. 5 for 5 MB.
3. Download the result. It comes back at or under your number.

No signup, no watermark, and the file (and result) auto-delete within 12 hours.

Why "target size," not "quality preset," is the thing that matters

A preset compresses by a fixed recipe regardless of your file. The same "Medium" setting turns a 40 MB scanned report into 12 MB and a 3 MB deck into 2.9 MB — neither of which might be the number you actually need. You're optimising a knob when you have a budget.

Target-size compression inverts it: you state the budget, and the tool works backwards to hit it. Under the hood, SourceBack:

• re-encodes and downsamples the images (that's where almost all the bytes live), then
• binary-searches the quality/resolution until the file lands at or just under your

target, keeping the highest quality that still fits, and

• keeps text selectable while it does this — it's compressing the images, not flattening

your document to a picture.

If a target is so small it's only reachable by rasterising the pages (turning text into an image), the tool tells you that up front and lets you choose — it doesn't silently wreck your document to hit a number.

Where the free tools and the paid tools each fall short

Being fair about the alternatives, because it matters:

The big names — iLovePDF, Smallpdf — are excellent at bulk and own the head-term "compress pdf" traffic; if you just want "smaller," they're right there. The point of a target-size tool is the specific job they don't do for free: hit a number, exactly, without paying or signing up.

Common target sizes (and where they come from)

• 25 MB — Gmail / most email attachment limits.
• 10 MB — a very common upload-form and ATS (job portal) cap.
• 5 MB — client portals, CMS uploads, many web forms.
• 2 MB — legacy government/university submission systems.

Set the one you need and skip the trial-and-error.

FAQ

Will the quality be bad? It keeps the highest quality that still fits your target — it only compresses as much as it has to. For a modest target on an image-heavy PDF the difference is usually invisible on screen; for an aggressive target you'll see softer images, which is the honest trade-off of asking for a small file.

Does the text stay selectable / searchable? Yes — it compresses the images and structure, not the text, so text stays selectable. The only exception is if you choose to rasterise pages to force a very small target.

Is it really free, with no account? Yes. The compressor is free with no signup — it's how most people first meet SourceBack.

Is my file private? Your upload and the compressed result auto-delete within 12 hours, and nothing is reused.

Compress a PDF to an exact size now — free, no signup: sourceback.app.