Is UnderLimit a free PDF compressor?

You can analyse files before compression. Compression runs with a one-time Single Batch (£4.99) or a subscription (Monthly £2.99/month or Annual £29.90/year). We do not market paid compression as “free”.

Do I need a subscription to use UnderLimit?

No. You can process one batch for £4.99 with a one-time payment, or choose a Monthly or Annual subscription if you use UnderLimit regularly.

Can I set a custom size?

Yes. Use a curated preset or enter a custom megabyte target in the tool when your portal uses a less common limit.

Will text stay selectable?

Preserve and Balanced aim to keep text usable when the file structure allows. Strong may rasterize pages when that is the only way to approach a tight target.

Compress PDFs to a specific file size

UnderLimit is built for upload limits—not vague “make it smaller” guesses. Pick a target size, analyse your PDFs, then compress toward that limit with Preserve, Balanced, or Strong.

Drop up to 20 PDFs here

Max 150 MB per file · 500 MB total

Files are scanned before analysis.

Target

Mode

Up to 20 PDFs
Background processing
Email delivery
48-hour secure access

Popular PDF size limits

Choose a target size

Common portal and mailbox ceilings include 1, 2, 5, 10, 20, 25, and 50 MB. Start with the limit you actually need, then adjust if preflight shows a readability trade-off.

Compress multiple PDFs

Upload up to 20 PDFs in one batch (150 MB per file, 500 MB total). Process in the background, then download files individually or as a ZIP while results stay available for about 48 hours.

Scanned PDFs need a different approach

Image-heavy scans are often the reason a file will not fit an upload form. Preflight helps you see when Balanced or Strong is required—and when a higher target is the better choice.

How UnderLimit works

Upload → security scan → size analysis → choose mode → compress → email or browser download. You see the estimate before you commit to compression.

Secure delivery

Files are scanned before processing, used only to prepare your download, and expire automatically. We do not train models on your documents.

Choose how you want to use UnderLimit

Single Batch
£4.99
One-time payment
Process one batch of up to 20 PDFs
Monthly
£2.99/month
Subscription
For ongoing PDF processing
Annual
£29.90/year
Subscription
Same subscription features, billed yearly
Save £5.98 compared with 12 monthly payments.

Compress a PDF

Related use cases

Related guides

How to reduce PDF file size
A practical path from diagnosis to a concrete megabyte target.
Why is my PDF so large?
Scans, images, exports, and other common size drivers.
How PDF compression works
Images, cleanup, rasterisation, and Preserve / Balanced / Strong.

FAQ

Is UnderLimit a free PDF compressor?: You can analyse files before compression. Compression runs with a one-time Single Batch (£4.99) or a subscription (Monthly £2.99/month or Annual £29.90/year). We do not market paid compression as “free”.
Do I need a subscription to use UnderLimit?: No. You can process one batch for £4.99 with a one-time payment, or choose a Monthly or Annual subscription if you use UnderLimit regularly.
Can I set a custom size?: Yes. Use a curated preset or enter a custom megabyte target in the tool when your portal uses a less common limit.
Will text stay selectable?: Preserve and Balanced aim to keep text usable when the file structure allows. Strong may rasterize pages when that is the only way to approach a tight target.