bcRPN vs HP
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
bcRPN
This utility app functions as a Reverse Polish Notation calculator. It handles complex numbers and utilizes extended precision for all calculations, offering an unlimited stack depth and an undo feature for up to 10 operations.
- Reverse Polish Notation (RPN) input
- Complex number calculations
- Extended precision math
- Unlimited stack depth
- Undo functionality (up to 10 operations)
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This is a RPN (Reverse Polish Notation) Calculator. It supports complex numbers and uses extended precision math for all operations. The stack depth is unlimited. In case a mistake was made, up to 10 operations can be undone. RPN calculators work by entering the numbers on the stack first, then selecting the operation. For example to add 3 + 4, press: 3 Enter 4 +
HP
Emulates classic Hewlett Packard RPN scientific calculators from the 1970s. Experience the original HP-35, HP-45, and HP-21 models on your iPhone.
- RPN calculator emulation
- HP-35 model
- HP-45 model
- HP-21 model
- Classic scientific calculator interface
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The classic Hewlett Packard RPN (Reverse Polish Notation) calculators. - HP-35, HP-45. First pocket scientific calculators (1972). - HP-21. 2nd gen of the HP-35 (1975)
Screenshots
Verdict
The clearest difference is update cadence: HP at every 11 days against bcRPN's every 22 months. HP also leads on review sentiment (100% vs 80%) and ratings volume (65 vs 8). bcRPN's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.2). On price, rating, ads and in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.
bcRPN holds the better App Store score, 4.8 against 4.6. That said, the two scores are not equally well evidenced: HP has 65 ratings behind it against 8, so its average is the more settled of the two. Written reviews complicate that: 80% of bcRPN's written reviews are positive against 100% of HP's, so the app with the better star average is not the one people write more warmly about.
bcRPN ships an update every 22 months, HP every 11 days. The most recent releases landed on November 3, 2026 and November 8, 2026 respectively.
| Parameter | bcRPN | HP |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (8 ratings) — better | 4.6 (65 ratings) |
| Positive reviews | 80.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 8 | 65 — better |
| Update frequency | Every 22 months | Every 11 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 17.2 |
| Further details — not scored | ||
| Size | 0 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Paul Wilkins | Enrique Haro |
Customer experience
bcRPN
HP
In-app purchases
bcRPN
No in-app purchases
HP
No in-app purchases
