# Calca vs Zotero

The clearest difference is price: Zotero at Free against Calca's $9.99. Zotero also leads on in-app purchases (none vs 2) and update cadence (every 3 weeks vs every 5 months). On rating, review sentiment, ratings volume and ads there is nothing between them.

Zotero is free to download; Calca costs $9.99 up front. Calca sells 2 one-off in-app purchases. Zotero asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.5 for Calca against 4.6 for Zotero. Both are backed by a comparable volume of ratings — 157 and 435 respectively. Written reviews are what separate them: 76% of Calca's written reviews are positive against 78% of Zotero's.

Calca ships an update every 5 months, Zotero every 3 weeks. The most recent releases landed on October 26, 2026 and October 27, 2026 respectively.

## The numbers

| Metric | Calca | Zotero |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | [4.5 (157 ratings)](https://appshunter.io/ios/app/calca/id635757879/reviews) | **[4.6 (435 ratings)](https://appshunter.io/ios/app/zotero/id1513554812/reviews)** |
| Number of ratings | 157 | **435** |
| Positive reviews | 76.5% of reviews | **77.9% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 78 MB | 237 MB |
| Requires iOS | **15.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Krueger Systems, Inc.](https://appshunter.io/developer/299293363) | [Zotero](https://appshunter.io/developer/1513554811) |

## What reviewers say

### Calca

[App page](https://appshunter.io/ios/app/calca/id635757879)

This app is an advanced symbolic calculator and text editor. It solves equations, simplifies expressions, and allows you to explain your work alongside calculations. Calculations update instantly as you type, and all data is stored as plain text for easy sharing and device syncing.

**Highlights:** Symbolic calculation, Equation solving, Expression simplification, Markdown text editor, Real-time updates, Unit and currency conversion, Matrix operations

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 6-Month Optional Patronage | $4.99 | one-time |
| 12-Month Optional Patronage | $7.99 | one-time |

**What reviewers like**

- 💡 Unique blend of text editor and calculator
- 📝 Markdown support for documentation
- 🔄 Dynamic recalculation of all values
- ⚙️ Powerful mathematical and algebraic capabilities
- 📊 Unit conversion and unit-aware calculations

**What reviewers complain about**

- 🐛 Magic Keyboard input bugs on iPad
- ⚠️ Appears abandoned or poorly maintained
- 🐛 Text selection issues with external keyboards
- 📱 iPad landscape mode problems
- 🐛 Cursor jumping and screen jumping during editing

**Reported bugs**

- Magic Keyboard causes number input to overwrite instead of append
- Text selection before numbers triggers increment/decrement instead of selecting
- Cursor jumps forward and backward with external keyboards
- iPad Pro keyboard truncation in portrait mode
- Arrow key (=>) doesn't work in landscape mode

**Requested features**

- Files app and document browser integration
- Dropbox and Google Drive support
- Date calculation functionality
- Looping and iteration support
- User-defined function storage in separate files


### Zotero

[App page](https://appshunter.io/ios/app/zotero/id1513554812)

This research tool helps you collect, organize, annotate, cite, and share your academic and professional work. Save articles, books, and webpages, add notes and highlights, and generate bibliographies in thousands of styles. Collaborate with others and sync your library across devices.

**Highlights:** Collect research from various sources, Organize with collections and tags, Annotate PDFs and webpages, Generate citations and bibliographies, Collaborate in group libraries, Sync across devices

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 👍 Simple and powerful
- 🚀 Convenient and useful
- 🚀 Seamless syncing across devices
- 🚀 Excellent reference management
- 👍 Great annotation and PDF reading experience

**What reviewers complain about**

- 🐛 Crashes frequently
- 🐛 Syncing issues with WebDAV
- 🐛 Metadata not automatically extracted from PDFs
- 🐛 Annotation tools could be improved
- 🐛 Limited sorting and filtering options

**Reported bugs**

- Unable to unzip PDF snapshots
- Annotations disappearing or moving unexpectedly
- Dark mode not working as expected
- Inability to add citations directly from the app

**Requested features**

- Eraser tool for annotations
- More color options for pen and highlighter
- Ability to open PDFs in external apps
- Bookmarking and table of contents support
- Improved search functionality


## Frequently asked questions

### Is Calca free?

Calca costs $9.99, and also offers in-app purchases.

### Is Zotero free?

Zotero is free to download, with no in-app purchases.

### Which has better reviews, Calca or Zotero?

Zotero is rated higher. Calca averages 4.5 out of 5 from 157 ratings, while Zotero averages 4.6 from 435 ratings.

### Do Calca or Zotero have ads?

Neither Calca nor Zotero shows ads.

### Which is updated more often, Calca or Zotero?

Calca ships an update every 5 months, and Zotero every 3 weeks. Most recently, Calca was updated on October 26, 2026 and Zotero on October 27, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*