PCalc vs Memory Knots
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PCalc
A powerful calculator designed for professionals and students, offering advanced features like RPN mode, multi-line display, and extensive unit conversions. It supports various number systems and includes an Apple Watch app for on-the-go calculations.
- Optional RPN mode
- Multi-line display
- Extensive unit conversions
- Paper tape
- Multiple undo/redo
- Hexadecimal, octal, binary support
- 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. Includes an Apple Watch app, so you can calculate on your wrist!
Memory Knots
Enhance your recall with color-coded reminders that are always accessible. This tool is ideal for managing multiple tasks, from academic schedules to daily errands, ensuring you stay organized and on track.
- Color-coded memory hints
- Intuitive reminder system
- Task management for busy individuals
- Watch face complications for quick access
- Instant app access from watch face
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You never forget anything - sometimes all you need is a little hint. Give your memory a boost with intuitive, color coded reminders. Always on your wrist, they are perfect for anyone juggling multiple tasks - a student staying on top of exams and assignments, a nurse looking after many patients, a busy mom running from soccer to bake sales and sleepovers. This simple little app will let you stay on top of your game, all day, every day! Complications (added in v.2) are available on most watch faces. They show a total number of To Do items and allow instant app access from the watch face.
Screenshots
Verdict
The clearest difference is review sentiment: PCalc at 84% against Memory Knots's 33%. PCalc also leads on rating (4.7 vs 3.4) and update cadence (every 6 weeks vs every 23 months). Memory Knots's advantage is price ($0.99 vs $9.99) and in-app purchases (none vs 4). On ads 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
PCalc costs $9.99 and Memory Knots $0.99 up front. PCalc sells 4 one-off in-app purchases. Memory Knots asks for nothing beyond the download.
PCalc holds the better App Store score, 4.7 against 3.4. That said, the two scores are not equally well evidenced: PCalc has 770 ratings behind it against 9, so its average is the more settled of the two. Written reviews point the same way: 84% of PCalc's written reviews are positive against 33% of Memory Knots's.
PCalc ships an update every 6 weeks, Memory Knots every 23 months. The most recent releases landed on September 30, 2026 and September 24, 2026 respectively.
| Parameter | PCalc | Memory Knots |
|---|---|---|
| Price | $9.99 | $0.99 — better |
| Rating | 4.7 (770 ratings) — better | 3.4 (9 ratings) |
| Positive reviews | 83.6% of reviews — better | 33.3% of reviews |
| Number of ratings | 770 — better | 9 |
| Update frequency | Every 6 weeks — better | Every 23 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Best chart rank | #76 — better | — |
| Devices | iPhone, iPad, iPod, Apple Watch, Vision Pro — better | iPhone, Apple Watch |
| Requires iOS | 15.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 81 MB | 3 MB |
| Age rating | 4+ | 9+ |
| Developer | TLA Systems Ltd. | Golmium |
Customer experience
PCalc
Memory Knots
In-app purchases
PCalc
- Small Tip$0.99
- Medium Tip$1.99
- Large Tip$4.99
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- Enormous Tip$9.99
Memory Knots
No in-app purchases
