RPN vs Nixie Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RPN
This app is a faithful simulation of a rare 1974 financial calculator, offering all its original functions with enhanced features like more memory registers and a visual stack display. It's designed for users who appreciate vintage technology and need precise financial calculations.
- Photo-realistic vintage calculator design
- Full HP-70 function simulation
- Animated keys with sound
- Enhanced stack and memory register view
- Cut/copy/paste display value
- Input parameter visual indicators
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RPN-70 SD is a complete simulation of the financial hand-held calculator HP-70 from 1974. It handles loan amortization, saving plans, depreciation, and much more with ease. What users said: "Looks good, all functions you need. Love it!" "This is a beautiful emulation of a very rare HP financial calculator from 1974. Works just like the original but better! Faster, more accurate, with 10 more storage registers, and a popup window lets you see the contents of each stack, financial and storage register. Provides TVM4 functionality for compound interest as well as accumulated simple interest. A true work of art!" Features: • Photo-realistic look based on an existing device • Animated keys with click sound (adjustable volume) • All functions and operations of the HP-70 fully implemented • Correct wrong number entries by swiping across the display • Cut/copy/paste of display value • Double-tap display to view the stack and memory registers • Visual indicators keep track of input parameters entered • 10 non-volatile memory registers (not available in original HP-70) The HP-70 was discontinued after just one year. It is one of the rarest calculators, hard to find in any condition. NOTE: RPN-70 SD is a faithful simulation of a vintage HP-70 calculator, as has been verified against a real device using the examples in the Applications Cookbook section of the HP-70 manual. In certain cases, what may appear like a bug of the app is actually an idiosyncrasy of the HP-70. IMPORTANT: The HP-70 requires exactly three input parameters from the top-row keys, at least one of them being either "n" or "i". In other words, you can't use PMT, PV, and FV as input parameters simultaneously. A version for the iPhone named "RPN-70 HD" is also available. Short manual and sample calculations on the website: www.cuveesoft.ch
Nixie Calculator
This calculator app features a digital paper tape to display entries, which can be copied or shared. It offers various customization options like color schemes, rounding, and display modes, blending retro aesthetics with modern device technology.
- Paper tape for entry display
- Copy and paste functionality
- Customizable color schemes
- Adjustable rounding and exponential modes
- Classic Nixie font option
- Thousand separator styles
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Features of Nixie Calculator: • Paper tape to display what you have entered. Can be copied or shared • Copy and paste entries Settings available: • Color schemes • Color layouts (in-app purchase) • Rounding options • Exponential modes • Use classic Nixie font for the display • Separators embedded with the digits • Classic pyramid and illuminated thousand separators • Classic red filter The calculator is a rounding or truncating type to fit numbers into the fixed display. Please enjoy this calculator that combines one of the first display technologies with state of the art in phone and tablet technology.
Screenshots
Verdict
The clearest difference is in-app purchases: RPN at none against Nixie Calculator's 1. RPN also leads on review sentiment (100% vs 67%) and iOS requirement (12.0 vs 15.0). Nixie Calculator's advantage is update cadence (monthly vs every 7 months). On price, rating, ratings volume and 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
Both are free to download. Nixie Calculator sells 1 one-off in-app purchase. RPN asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.7 for RPN against 4.9 for Nixie Calculator. Both are backed by a comparable volume of ratings — 11 and 15 respectively. Written reviews are what separate them: 100% of RPN's written reviews are positive against 67% of Nixie Calculator's.
RPN ships an update every 7 months, Nixie Calculator monthly. The most recent releases landed on November 1, 2026 and October 24, 2026 respectively.
| Parameter | RPN | Nixie Calculator |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (11 ratings) | 4.9 (15 ratings) — better |
| Positive reviews | 100.0% of reviews — better | 66.7% of reviews |
| Number of ratings | 11 | 15 — better |
| Update frequency | Every 7 months | Monthly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 17 MB | 36 MB |
| Age rating | 4+ | 4+ |
| Developer | CuVee Software | UNB SYSTEMS PTY LTD |
Customer experience
RPN
Nixie Calculator
In-app purchases
RPN
No in-app purchases
Nixie Calculator
- Color Layouts$2.99









