Comparison

ThetaCalc vs Zero Duplicates

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

Head to head
About

ThetaCalc

This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.

Highlights
  • Reverse Polish Notation (RPN) calculator
  • User-programmable functions
  • JavaScript equation support
  • Extensible functionality
Features
Read full description

ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.

About

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.

Highlights
  • 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
Read full description

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

ThetaCalc4 screens
Zero Duplicates4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

ThetaCalc ships an update every 3 months, Zero Duplicates weekly. The most recent releases landed on June 1, 2026 and September 18, 2026 respectively.

Scorecard6 real differences · 4 level
ThetaCalc versus Zero Duplicates: the parameters behind the verdict, then further details
ParameterThetaCalcZero Duplicates
PriceFreeFree
Rating4.3 (4 ratings)4.9 (47 ratings) — better
Positive reviews100.0% of reviews — better66.7% of reviews
Number of ratings447 — better
Update frequencyEvery 3 monthsWeekly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFreemium
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.617.0 — better
Further details — not scored
Size1 MB15 MB
Age rating4+4+
DeveloperFelix StehliChristopher Brock

Customer experience

ThetaCalc

All ratings4 ratings
Positive75.0%
Neutral25.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Zero Duplicates

All ratings47 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive66.7%
Neutral0.0%
Negative33.3%

In-app purchases

None

ThetaCalc

No in-app purchases

3 purchases

Zero Duplicates

Subscriptions2
  • Monthly Subscription$1.991 Month
  • Yearly Subscription$5.991 Year
One-time1
  • Lifetime$14.99

Questions

Is ThetaCalc free?
ThetaCalc is free to download, with no in-app purchases.
Is Zero Duplicates free?
Zero Duplicates is free to download, with in-app purchases available.
Which has better reviews, ThetaCalc or Zero Duplicates?
Zero Duplicates is rated higher. ThetaCalc averages 4.3 out of 5 from 4 ratings, while Zero Duplicates averages 4.9 from 47 ratings.
Do ThetaCalc or Zero Duplicates have ads?
Neither ThetaCalc nor Zero Duplicates shows ads.
Which is updated more often, ThetaCalc or Zero Duplicates?
ThetaCalc ships an update every 3 months, and Zero Duplicates weekly. Most recently, ThetaCalc was updated on June 1, 2026 and Zero Duplicates on September 18, 2026.

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