Comparison

PDF Size Reducer & Compressor vs UnderMB

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

PDF Size Reducer & Compressor

Features
Read full description

Is your PDF too big to email, upload or share? PDF Size Reducer makes large PDF files smaller in seconds, right on your iPhone or iPad. Just select a PDF, choose a compression level and tap Compress. You'll instantly see the original size, the new size and how much space you saved. Then share or save your file anywhere with one tap. WHY PDF SIZE REDUCER? • Fast & simple – Select, compress, done. No complicated settings. • Choose your quality – Low for maximum compression, Medium for a balance of size and clarity, or High for the best image quality. • Before & after comparison – See exactly how many MB you saved on every file. • Private by design – Your PDFs are processed on your device. Your documents are not uploaded to our servers. • Smart protection – If a PDF is already as small as it can be, your original file is kept unchanged. • Compression history – Find, re-share or recompress your recent files anytime. • Share anywhere – Send compressed PDFs via Mail, Messages, WhatsApp, or save them to Files and iCloud Drive. PERFECT FOR • Email attachments that exceed size limits • Uploading documents to job applications, school portals and government websites • Sending invoices, contracts, scanned documents and reports • Freeing up storage space on your device PDF SIZE REDUCER PRO Upgrade to Pro to unlock everything: • Unlimited compressions • High Quality mode • Batch compression – compress multiple PDFs at once and share them all together • PDF editing – rotate, reorder and delete pages before compressing • Full compression history Free users can compress 1 PDF per day. SUBSCRIPTION INFORMATION PDF Size Reducer Pro is available as an auto-renewable subscription. Payment will be charged to your Apple ID account at confirmation of purchase. The subscription automatically renews unless it is canceled at least 24 hours before the end of the current period. Your account will be charged for renewal within 24 hours prior to the end of the current period. You can manage and cancel your subscription in your App Store account settings after purchase. Any unused portion of a free trial period, if offered, will be forfeited when you purchase a subscription. CONTACT & SUPPORT Need help or have a suggestion? Contact us: https://upbeat-animantarx-f5b.notion.site/SUPPORT-2ebee4e7706780c7a2d5c496801eed5b?source=copy_link Terms of Use: https://upbeat-animantarx-f5b.notion.site/PDF-Compressor-Terms-Conditions-2edee4e770678011bdecca736c82cdc0?source=copy_link Privacy Policy: https://upbeat-animantarx-f5b.notion.site/PDF-COMPRESSOR-Privacy-Policy-2edee4e7706780f1a67ef10873dadf7b?source=copy_link

About

UnderMB

Reduce the size of photos, videos, audio, and PDFs on your device. Select a target file size or use presets for common uploads like email or chat apps. Preview your compressed files before saving or sharing, with optional metadata removal.

Highlights
  • Compress images, videos, audio, and PDFs
  • Choose target file size (KB/MB)
  • Built-in presets for uploads
  • Preview before saving
  • Optional metadata removal
  • Batch processing
Features
Read full description

UnderMB helps you reduce photo, video, audio, and PDF file sizes to fit common upload limits. Processing happens on your device. WHAT IT DOES • Choose a target size: 500 KB, 1 MB, 2 MB, 5 MB, or a custom value • Compress images, videos, audio files, and PDFs • Preview results before saving or sharing • Built-in presets for email, visa forms, WhatsApp, and similar uploads • Optional metadata removal (EXIF/GPS, PDF info) • Batch queue for multiple files • Save to Files or share from the app PRIVACY UnderMB does not require an account. Files are processed locally and are not uploaded to UnderMB servers. GOOD FOR • Forms and portals with file size limits • Smaller email attachments • Chat apps with upload caps • Reducing file size before sharing

Screenshots

PDF Size Reducer & Compressor4 screens
UnderMB4 screens

Verdict

The call

The clearest difference is in-app purchases: UnderMB at none against PDF Size Reducer & Compressor's 2. UnderMB also leads on update cadence (every 11 days vs every 3 weeks) and iOS requirement (15.0 vs 17.0). PDF Size Reducer & Compressor's advantage is ads (none vs shown). On price and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. PDF Size Reducer & Compressor sells 2 in-app purchases, starting at $2.99 per 7 days. UnderMB asks for nothing beyond the download.

UpkeepUpdate frequency

PDF Size Reducer & Compressor ships an update every 3 weeks, UnderMB every 11 days. The most recent releases landed on November 9, 2026 and October 31, 2026 respectively.

Scorecard4 real differences · 5 level
PDF Size Reducer & Compressor versus UnderMB: the parameters behind the verdict, then further details
ParameterPDF Size Reducer & CompressorUnderMB
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyEvery 3 weeksEvery 11 days — better
AdsNo — betterYes
In-app purchasesYesNo — better
Monetization—Ad-supported
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.015.0 — better
Further details — not scored
Size10 MB9 MB
Age rating4+4+
DeveloperBaris Mustafa Han UnluCEMRE SIMSEK

In-app purchases

2 purchases

PDF Size Reducer & Compressor

Subscriptions2
  • PDF Compress$2.997 Days
  • Smart Compression$5.991 Month
None

UnderMB

No in-app purchases

Questions

Is PDF Size Reducer & Compressor free?
PDF Size Reducer & Compressor is free to download, with in-app purchases available.
Is UnderMB free?
UnderMB is free to download, with no in-app purchases.
Do PDF Size Reducer & Compressor or UnderMB have ads?
UnderMB shows ads; PDF Size Reducer & Compressor does not.
Which is updated more often, PDF Size Reducer & Compressor or UnderMB?
PDF Size Reducer & Compressor ships an update every 3 weeks, and UnderMB every 11 days. Most recently, PDF Size Reducer & Compressor was updated on November 9, 2026 and UnderMB on October 31, 2026.

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