Comparison

ThetaCalc vs EPUB2PDF

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

EPUB2PDF

Features
Read full description

EPUB to PDF is a simple and fast tool dedicated to converting between EPUB and PDF formats. With just one tap, you can convert your files in seconds. Core Features EPUB to PDF: Convert EPUB ebooks to PDF while preserving the original layout, images, and table of contents. PDF to EPUB: Convert PDF documents to EPUB format for easy reading on ebook readers. One‑tap operation: Select your file, tap convert, and you're done in seconds. Offline support: All conversion happens locally on your device. No file upload required, ensuring your privacy. Use Cases Reading enthusiasts: Convert EPUB to PDF for easy printing or archiving. Professionals: Convert PDF to EPUB to read documents on mobile devices or ebook readers. Students and teachers: Convert educational materials to fit different devices. Download EPUB to PDF Simple, fast, no learning curve. Download now and experience one‑tap conversion. —Subscription Plans & Auto-Renewal Info Flexible Subscription Plans for Every Need! Choose the perfect plan for your goals with our diverse subscription options: * 1 Month: Ideal for project-based users * 1 Year: Best value for committed users —Auto-Renewal Details: * Payment will be charged to your iTunes Account at confirmation of purchase. * Subscriptions are billed weekly, monthly, bi-monthly, quarterly, semi-annually, or annually based on your chosen plan. * Subscriptions auto-renew within 24 hours before the current period ends (except Lifetime). * Renewal charges will be processed within 24 hours before the end of the current period, with the cost depending on your selected plan. * Manage subscriptions or turn off auto-renewal anytime via your Apple ID Account Settings. —Lifetime Membership Perks: * Pay once, unlock all features forever—no renewals, no hassle! Note: * Manage subscriptions at: Settings > [Your Name] > Subscriptions — Privacy Policy please visit: https://docs.qq.com/doc/DREt1SXJkbG9JYUFT * **Terms of use (EULA): * https://docs.qq.com/doc/DREdKR2ZwYUJaa1hr * **Terms of apple please visit: * https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ For support or feedback, contact: hxx_shdt@126.com

Screenshots

ThetaCalc4 screens
EPUB2PDF3 screens

Verdict

The call

The clearest difference is price: ThetaCalc at Free against EPUB2PDF's $0.99. ThetaCalc also leads on in-app purchases (none vs 3). On update cadence, 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

ThetaCalc is free to download; EPUB2PDF costs $0.99 up front. EPUB2PDF sells 3 in-app purchases, starting at $3.99 per month. ThetaCalc asks for nothing beyond the download.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 months. The most recent releases landed on October 1, 2026 and October 16, 2026 respectively.

Scorecard2 real differences · 8 level
ThetaCalc versus EPUB2PDF: the parameters behind the verdict, then further details
ParameterThetaCalcEPUB2PDF
PriceFree — better$0.99
Rating4.3 (4 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings4 — better—
Update frequencyEvery 3 monthsEvery 3 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.617.6
Further details — not scored
Size1 MB18 MB
Age rating4+4+
DeveloperFelix Stehli乐祥 胡

In-app purchases

None

ThetaCalc

No in-app purchases

3 purchases

EPUB2PDF

Subscriptions2
  • EPUB2PDF Premium - 30DAYS$3.991 Month
  • EPUB2PDF Premium - 360DAYS$3.991 Year
One-time1
  • EPUB2PDF Premium - lifetime$7.99

Questions

Is ThetaCalc free?
ThetaCalc is free to download, with no in-app purchases.
Is EPUB2PDF free?
EPUB2PDF costs $0.99, and also offers in-app purchases.
Do ThetaCalc or EPUB2PDF have ads?
Neither ThetaCalc nor EPUB2PDF shows ads.
Which is updated more often, ThetaCalc or EPUB2PDF?
ThetaCalc ships an update every 3 months, and EPUB2PDF every 3 months. Most recently, ThetaCalc was updated on October 1, 2026 and EPUB2PDF on October 16, 2026.

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