ThetaCalc vs Zero Duplicates
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ThetaCalc
This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.
- Reverse Polish Notation (RPN) calculator
- User-programmable functions
- JavaScript equation support
- Extensible functionality
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ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.
Zero Duplicates
Reclaim iPhone storage by finding and deleting duplicate files, even those with different names. Advanced content analysis ensures accurate identification, and a privacy-first design keeps your data local. Safely organize documents, images, videos, and more.
- Advanced content analysis for real duplicates
- Finds duplicates with different filenames
- Supports documents, images, videos, audio, and downloads
- Scans iCloud Drive and external storage
- Privacy-first local scanning
- Auto-select duplicates by newest/oldest
- Preview before deleting
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Most cleaning apps on the App Store focus on the photo library. Zero Duplicates focuses on your files: the downloads, documents, PDFs, videos and audio files that pile up in the Files app and quietly fill your storage. Zero Duplicates compares files by their content, not by their names. A renamed download, an attachment saved twice, a document copied into three folders: all of them are found, even when the file names look nothing alike. MADE FOR THE FILES ON YOUR DEVICE • Scan any folder you choose: On My iPhone, iCloud Drive, external drives • Downloads from Safari, Mail and Messages • Documents: PDF, Word, Excel, Pages, Numbers, Keynote • Images, videos, audio recordings, archives and more • USB drives and SD cards (with adapter) CONTENT MATCHING File names lie. Zero Duplicates reads the actual content of every file, so duplicates are found even when they were renamed, moved or saved from different apps. AUTO-SELECT IN SECONDS Automatic selection keeps the newest or the oldest file in every duplicate group. Review, tap once, done. No scrolling through hundreds of files by hand. SEE BEFORE YOU DELETE Every duplicate can be previewed before deletion, and you choose which copy stays. At least one version of every file always remains, so losing all copies is impossible. Deletion is permanent, so nothing is removed without a clear confirmation first. PRIVATE BY DESIGN Scanning happens entirely on your device. Your files are never uploaded anywhere. HOW IT WORKS Pick a folder, scan, review what was found, delete with confidence. Three steps to a cleaner device. System files are protected automatically. Perfect for: • Anyone seeing "Storage Almost Full" warnings • People who download and share lots of files • Managing documents, media and work files on the go • Cleaning up iCloud Drive across devices TRY WITHOUT RISK Free to download • Unlimited scans • 500 MB free deletion Premium unlocks unlimited deletion and advanced features. Terms of Use: https://zeroduplicates.com/terms
Screenshots
Verdict
The clearest difference is rating: Zero Duplicates at 4.9 against ThetaCalc's 4.3. Zero Duplicates also leads on update cadence (weekly vs every 3 months) and ratings volume (47 vs 4). ThetaCalc's advantage is in-app purchases (none vs 3) and review sentiment (100% vs 67%). On price, ads, device support and iOS requirement 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
Both are free to download. Zero Duplicates sells 3 in-app purchases, starting at $1.99 per month. ThetaCalc asks for nothing beyond the download.
Zero Duplicates holds the better App Store score, 4.9 against 4.3. That said, the two scores are not equally well evidenced: Zero Duplicates has 47 ratings behind it against 4, so its average is the more settled of the two. Written reviews complicate that: 100% of ThetaCalc's written reviews are positive against 67% of Zero Duplicates's, so the app with the better star average is not the one people write more warmly about.
ThetaCalc ships an update every 3 months, Zero Duplicates weekly. The most recent releases landed on June 1, 2026 and September 18, 2026 respectively.
| Parameter | ThetaCalc | Zero Duplicates |
|---|---|---|
| Price | Free | Free |
| Rating | 4.3 (4 ratings) | 4.9 (47 ratings) — better |
| Positive reviews | 100.0% of reviews — better | 66.7% of reviews |
| Number of ratings | 4 | 47 — better |
| Update frequency | Every 3 months | Weekly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Freemium |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.6 | 17.0 — better |
| Further details — not scored | ||
| Size | 1 MB | 15 MB |
| Age rating | 4+ | 4+ |
| Developer | Felix Stehli | Christopher Brock |
Customer experience
ThetaCalc
Zero Duplicates
In-app purchases
ThetaCalc
No in-app purchases
Zero Duplicates
- Monthly Subscription$1.991 Month
- Yearly Subscription$5.991 Year
- Lifetime$14.99









