RPN vs CatLabel
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RPN
This app emulates the first pocket scientific calculator, offering a photo-realistic vintage experience. It simulates original operating speeds and unique arithmetic bugs, with optional modern enhancements like non-volatile registers.
- Photo-realistic look-and-feel
- Multiple vintage skins
- Vintage and Enhanced modes
- Optional key-click and key-glow
- Swipe to correct input
- Display stack and memory registers
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On January 4, 1972, Hewlett-Packard announced the HP-35, world's first scientific calculator small enough to fit in a pocket - more precisely, Bill Hewlett's shirt-pocket. The HP-35 was an immediate hit with students, engineers, and scientists. Despite its steep price of $395 (about $3000 today), it sold ten times better than anticipated in the first year. Experience this unique calculator that won HP the prestigious "IEEE Milestone in Electrical Engineering and Computing" in 2009. Features: • Photo-realistic look-and-feel • Three skins: version 1, versions 2 & 3 (1973) and final version 4 (1974) • Vintage mode and Enhanced mode • Key-click and key-glow, both optional • Swipe left across display to correct number input errors • Cut/copy/paste display value • Display stack registers and memory registers • All decimal points but one light when iPhone battery charge drops below 5% Vintage mode In this mode, peculiarities of a real HP-35 are simulated: - original speed of operation - stack register Z copied to T on trig functions - leading zeros may be entered; zero can be made negative - a negative number may be entered by pressing CHS before or after the number - a keyboard entry or RCL immediately following STO does not raise the stack - for version 1 only: simulation of a number of known arithmetic bugs Enhanced mode - non-volatile stack and registers - use registers 1 through 9 with HP-45-like register arithmetic - register 0 works as LastX register
CatLabel
Create custom text and color labels for your device's home screen. Organize your pages with glanceable widgets, making navigation easier.
- Custom text labels
- Customizable colors
- Home screen widgets
- Improved page organization
- Glanceable information
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Widget for adding labels on the Home Screen, set custom texts and color to make your pages more easily glanceable.
Screenshots
Verdict
The clearest difference is rating: RPN at 4.4 against CatLabel's 2.7. RPN also leads on review sentiment (71% vs 50%) and update cadence (every 6 months vs every 19 months). CatLabel's advantage is price ($0.99 vs $1.99). On ads, in-app purchases, monetization model and device support 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
RPN costs $1.99 and CatLabel $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
RPN holds the better App Store score, 4.4 against 2.7. Both are backed by a comparable volume of ratings — 14 and 3 respectively. Written reviews point the same way: 71% of RPN's written reviews are positive against 50% of CatLabel's.
RPN ships an update every 6 months, CatLabel every 19 months. The most recent releases landed on November 4, 2026 and November 3, 2026 respectively.
| Parameter | RPN | CatLabel |
|---|---|---|
| Price | $1.99 | $0.99 — better |
| Rating | 4.4 (14 ratings) — better | 2.7 (3 ratings) |
| Positive reviews | 71.4% of reviews — better | 50.0% of reviews |
| Number of ratings | 14 — better | 3 |
| Update frequency | Every 6 months — better | Every 19 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 12.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 14 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | CuVee Software | Johan Jaderblom |
Customer experience
RPN
CatLabel
In-app purchases
RPN
No in-app purchases
CatLabel
No in-app purchases









