PCalc Lite vs Retro 15C
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PCalc Lite
This free scientific calculator offers essential features like RPN mode, unit conversions, and multiple undo/redo. It provides a taste of a more powerful version, with optional in-app purchases for expanded functionality.
- Optional RPN mode
- Multiple undo and redo
- Unit conversions and constants
- Two stylish themes
- Apple Watch app
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PCalc is the powerful choice for scientists, engineers, students, programmers, or indeed anybody looking for a feature rich calculator. It includes an optional RPN mode and multi-line display, a choice of button layouts, an extensive set of unit conversions and constants, a paper tape, multiple undo and redo, engineering and scientific notation, as well as support for hexadecimal, octal, and binary calculations.PCalc Lite is a fully functional and free taste of our very popular scientific calculator. It includes an optional RPN mode, multiple undo and redo, unit conversions and constants, as well as two stylish themes and our highly praised design. A great choice for your new iPad! If you like what you see, the full version has many more settings and themes, a paper tape, engineering and scientific notation, and full support for hexadecimal, octal, and binary calculations. You can also now purchase extra features directly from inside PCalc Lite. Buy them individually, or buy everything. Includes an Apple Watch app, so you can calculate on your wrist!
Retro 15C
This app emulates a classic RPN scientific calculator, offering advanced features like complex number arithmetic, matrix calculations, and programmability. It provides a functional and complex tool reminiscent of 1980s calculators.
- Complex number arithmetic
- Matrix calculations
- Numerical root finder
- Numerical integration
- Statistical functions
- Programmable
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Students and scientists from the 1980s will remember the classic RPN scientific calculators. These calculators strike a perfect balance between functionality and complexity. * Complex number arithmetic and trig functions * Matrix calculations * Numerical root finder * Numerical integration * Statistical functions, linear regression * Fully programmable This app is completely free, no ads or extra bits to buy. I love this calculator and I like to share.
Screenshots
Verdict
The clearest difference is in-app purchases: Retro 15C at none against PCalc Lite's 11. Retro 15C also leads on iOS requirement (8.0 vs 15.0). PCalc Lite's advantage is update cadence (every 2 months vs every 53 months) and device support (4 vs 2). On price, rating, review sentiment and ratings volume 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. PCalc Lite sells 11 one-off in-app purchases. Retro 15C asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.4 for PCalc Lite against 4.3 for Retro 15C. Both are backed by a comparable volume of ratings — 214 and 212 respectively. Written reviews are what separate them: 83% of PCalc Lite's written reviews are positive against 76% of Retro 15C's.
PCalc Lite ships an update every 2 months, Retro 15C every 53 months. The most recent releases landed on October 13, 2026 and October 7, 2026 respectively.
| Parameter | PCalc Lite | Retro 15C |
|---|---|---|
| Price | Free | Free |
| Rating | 4.4 (214 ratings) — better | 4.3 (212 ratings) |
| Positive reviews | 82.6% of reviews — better | 76.1% of reviews |
| Number of ratings | 214 — better | 212 |
| Update frequency | Every 2 months — better | Every 53 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod, Apple Watch — better | iPhone, iPod |
| Requires iOS | 15.0 | 8.0 — better |
| Further details — not scored | ||
| Size | 76 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | TLA Systems Ltd. | Greg Hewgill |
Customer experience
PCalc Lite
Retro 15C
User reviews
PCalc Lite
From 214 App Store ratingsWhat we love
- 🚀 Fast and responsive
- 👍 Clean and intuitive interface
- 💡 Customizable themes and settings
- 🚀 Efficient performance
- 👍 Useful conversion tools
Room to improve
- 🐛 Occasional lags and crashes
- 🔒 Lack of dark mode support
- 🔒 Inconsistent icon appearance after upgrades
- 🔒 Limitations in RPN mode on Apple Watch
- 🔒 Lack of financial calculator functions
Retro 15C
From 212 App Store ratingsWhat we love
- 🚀 Lightning-fast calculator
- 👍 Authentic look and feel of HP 15C
- 🚀 Faster than real HP 15C
- 👍 Excellent RPN emulation
- 👍 Familiar interface for HP 15C users
Room to improve
- 🐛 Doesn't save settings, programs, or memory
- 🐛 No key press feedback or sound
- 🐛 Blinking display issue with large calculations
- 🐛 Bugs with HMS conversions
- 🐛 Can't close app on newer iPhones
Bugs and requests
PCalc Lite
Reported bugs
3 issues- Calculations sometimes produce unexpected results
- Upside-down text censorship feature is problematic
- Purchased features not always accessible on Apple Watch
Requested features
4 requests- Add option to display thousands separators
- Implement a history function to review past calculations
- Provide more customization options for the widget
- Add support for sexagesimal angle input and conversion
Retro 15C
Reported bugs
4 issues- Blinking display with large calculations
- Bugs with HMS conversions
- Inability to close app on newer iPhones
- Stopped working with iOS 14 updates
Requested features
5 requests- Add haptic feedback on key presses
- Implement continuous memory to save settings and programs
- Add portrait mode option
- Improve compatibility with newer iOS versions
- Add copy/paste functionality for stack and registers
In-app purchases
PCalc Lite
- Theme Pack$0.99
- Power User Pack$0.99
- Multiple Line Pack$0.99
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- Conversion Pack$0.99
- Small Tip$0.99
- Medium Tip$1.99
- Programmer Pack$2.99
- Engineer Pack$2.99
- Large Tip$4.99
- Complete Pack$9.99
- Enormous Tip$9.99
Retro 15C
No in-app purchases
