Comparison

Calvin Opera vs Reformed Reader Plus

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

Head to head
About

Calvin Opera

Access the complete writings of John Calvin with fast search capabilities and an integrated Latin dictionary. This comprehensive collection is a primary resource for studying Calvin's extensive theological works.

Highlights
  • Complete Works of John Calvin
  • Fast search functionality
  • Integrated Latin dictionary
  • Primary source for Calvin studies
  • Organized by volume and content type
Features
Read full description

The ‘Complete Works of Calvin’ refers to ‘Ioannis Calvini opera quae supersunt omnia’ (‘All Surviving Works of John Calvin’), which were edited between 1863 and 1900 by Johann Wilhelm Baum, August Eduard Cunitz and Eduard Reuss, and were published in 59 volumes. As the title indicates, it is a collection of all the writings of Calvin which had survived up to that time. The ‘Complete Works of Calvin’ is commonly abbreviated to ‘CO’(Calvini Opera), but is also abbreviated to ‘CR’ because it forms vols. 29-87 of the ‘Corpus Reformatorum,’ which also includes the works of Reformers Philip Melanchthon and Huldrich Zwingli. Thus, the first volume of the ‘Complete Works of Calvin’ can be referred to as ‘CO 1’ or ‘CR 29.’ The ‘Complete Works of Calvin’ remains the best primary source for the study of Calvin. Since 1992, critical editions of Calvin’s works have been published, starting with ‘Opera Exegetica: Commentarii in Pauli Epistolas ad Galatas, ad Ephesios, ad Philippenses, ad Colossenses,’ ed. Helmut Feld (Geneva: Librairie Droz, 1992). This task is being undertaken by an international committee of members of the finest quality, affiliated with the International Congress on Calvin Research. The contents of the ‘Complete Works of Calvin’ are as follows: Vols. 1-4 contain the Institutes of the Christian Religion, Vols. 5-9 mainly short treatises, 10-20 Epistles, 21 the lives of Calvin, 22 the indices of vols. 1-21, 23-44 Old Testament commentaries and sermons, 45-55 New Testament commentaries and sermons, 56-57 Calvin’s French Bible, 58-9 additional sermons and indices to vols. 23-55. This App enables fast searches of the ‘Complete Works of Calvin’ and contains an easy-to-use Latin dictionary. This is the combined works of two organizations, PartPrime and KIRS(Korean Institute for Reformed Studies).

About

Reformed Reader Plus

Explore the core tenets of Reformed theology with a curated library of confessions and catechisms. Features include easy navigation, scripture proofs, memory functions, and advanced search capabilities for in-depth study.

Highlights
  • Curated Reformed confessions and catechisms
  • Easy navigation and intuitive interface
  • Scripture proofs for theological doctrines
  • Memory features for saving favorite sections
  • Advanced search for themes and doctrines
Features
Read full description

Discover the depth and richness of Reformed theology with our innovative app, designed to bring the timeless truths of Reformed confessions and catechisms right to your fingertips. Access a curated collection of Reformed confessions and catechisms, including the Westminster Confession of Faith, Heidelberg Catechism, and more. -Easy Navigation: Seamlessly explore the documents with an intuitive interface, making it simple to find and read specific sections or topics. -Scripture Proofs: Dive deeper into the foundational scripture proofs supporting each confession and catechism, enhancing your understanding and study. -Memory Features: Save your favorite sections and bookmark key passages for quick reference and ongoing reflection. -Dig Deeper: Utilize advanced search options to explore specific themes, doctrines, or scriptural references across the entire library.

Screenshots

Calvin Opera3 screens
Reformed Reader Plus4 screens

Verdict

The call

The clearest difference is price: Reformed Reader Plus at Free against Calvin Opera's $4.99. Reformed Reader Plus also leads on rating (5.0 vs 1.0) and update cadence (every 4 months vs every 9 months). On ratings volume, ads, in-app purchases 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

Reformed Reader Plus is free to download; Calvin Opera costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Reformed Reader Plus holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

UpkeepUpdate frequency

Calvin Opera ships an update every 9 months, Reformed Reader Plus every 4 months. The most recent releases landed on November 6, 2026 and October 30, 2026 respectively.

Scorecard5 real differences · 5 level
Calvin Opera versus Reformed Reader Plus: the parameters behind the verdict, then further details
ParameterCalvin OperaReformed Reader Plus
Price$4.99Free — better
Rating1.0 (1 ratings)5.0 (1 ratings) — better
Positive reviews100.0% of reviews—
Number of ratings11
Update frequencyEvery 9 monthsEvery 4 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS18.615.1 — better
Further details — not scored
Size1.6 GB32 MB
Age rating4+4+
Developerjeong youngohKenneth Brown

Customer experience

Calvin Opera

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Reformed Reader Plus

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Calvin Opera

No in-app purchases

None

Reformed Reader Plus

No in-app purchases

Questions

Is Calvin Opera free?
Calvin Opera costs $4.99, with no in-app purchases.
Is Reformed Reader Plus free?
Reformed Reader Plus is free to download, with no in-app purchases.
Which has better reviews, Calvin Opera or Reformed Reader Plus?
Reformed Reader Plus is rated higher. Calvin Opera averages 1.0 out of 5 from 1 ratings, while Reformed Reader Plus averages 5.0 from 1 ratings.
Do Calvin Opera or Reformed Reader Plus have ads?
Neither Calvin Opera nor Reformed Reader Plus shows ads.
Which is updated more often, Calvin Opera or Reformed Reader Plus?
Calvin Opera ships an update every 9 months, and Reformed Reader Plus every 4 months. Most recently, Calvin Opera was updated on November 6, 2026 and Reformed Reader Plus on October 30, 2026.

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