bcRPN vs echo
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 +
echo
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Echo is notes at the speed of a text. Open, type, send. Make quick lists. Sketch ideas. Use hashtags to organize. Start threads to group thoughts. Pin important notes. Search is instant. Sync across devices. Private by default. Minimal by design.
Screenshots
Verdict
The clearest difference is price: bcRPN at Free against echo's $2.99. bcRPN also leads on device support (3 vs 1) and iOS requirement (15.0 vs 26.0). echo's advantage is update cadence (every 3 days vs every 22 months). On 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
bcRPN is free to download; echo costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
bcRPN ships an update every 22 months, echo every 3 days. The most recent releases landed on October 7, 2026 and October 2, 2026 respectively.
| Parameter | bcRPN | echo |
|---|---|---|
| Price | Free — better | $2.99 |
| Rating | 4.8 (4 ratings) — better | — |
| Positive reviews | 80.0% of reviews | — |
| Number of ratings | 4 — better | — |
| Update frequency | Every 22 months | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 0 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Paul Wilkins | Arjun Mahanti |
In-app purchases
bcRPN
No in-app purchases
echo
No in-app purchases
