Codex Calc vs RPN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Codex Calc
This app offers a powerful yet intuitive calculator experience with a variety of modes including scientific, unit conversion, and tip calculation. It features a customizable interface and a detailed history tape for all your calculations.
- Full scientific calculator functions
- Unit converter
- Tip calculator
- RPN mode
- History tape
- Customizable interface
- Multiple visual themes
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Codex Calc is the calculator for the rest of us: easy and intuitive, without sacrificing power and capabilities. Calculator • Unit Converter • Tip Calculator • RPN Mode • Full Scientific • History Tape All the power you need, wrapped in a beautifully designed interface that's simple without being simplistic. ADAPTS TO YOU Do you like big buttons, or small? Like minimalist interfaces, or are you a fan of bright and flashy? Prefer small fonts to see more detail, or big text and easy to read buttons? Codex Calc adapts itself to the way *you* like to work. FEATURES Everything you'd expect, plus: • History tape records all entries and calculations • Full suite of standard and scientific calculator functions • Unit conversion mode for forward and reverse conversions • Full tip calculator mode - taxes, tip, per-person amounts • RPN mode fully integrated • Rotation lock and sound on/off toggles • Seven different professionally designed visual themes • Multi-number memory and full set of memory-store operators • Full control over history tape font size • Single and multiple-line history tape formats • Large and small button sizes • Settings for customization (number formatting, behavior of clear key, display of calculation details, much more) Calculations: • Trig functions in degrees and radians • Log and power/exponentials • Scientific notation / exponent mode • Rounding and truncating • Random number generation • Parenthesis and sub-expressions ...and more! INTUITIVE TOUCH INTERFACE Take full advantage of your device's capabilities: • Overlays - rather than making buttons smaller to fit more, Codex Calc uses intuitive overlays on the existing buttons. • Popup Menus - hidden until you need them, pop-up context menus give you more power when the default action isn't quite what you need. • Zoomable History Tape - Tap the history tape to expand for more detail, change the font size, copy contents to clipboard, or forward as an email. View as single-lines to save space, or use multi-line view for more detail. • Multiple Flexible Layouts - Portrait and landscape, large and small buttons, and seven different graphical themes. • Easy-Touch Everything - Codex Calc's entire design approach revolves around "touch to activate." Tap the tape to see it bigger, swipe to scroll, long-press a button for more options, tap the display to copy or paste, etc.
RPN
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The basic four function calculator displays numbers in fixed format. The scientific calculator has 75 built-in functions covering logarithms, powers, roots, trigonometric, date, time, memory operations, statistics, and probabilities and up to four user defined macro functions. It displays numbers in user configurable fixed, scientific, or engineering formats. The user configurable calculator has sixteen user configurable function buttons that can each be assigned two functions from 75 built-in functions and access an unlimited number of user defined macro functions. It displays numbers in user configurable fixed, scientific, or engineering formats. The programmer’s calculator has a hexadecimal keypad and displays numbers in user configurable hexadecimal format. It has four basic mathematics, six bitwise, and two shift functions. All calculators share an operation history display for ease of reviewing computations and extensive in-app help documentation. Numbers can be copied to and pasted from the clipboard for ease of use with other applications.
Screenshots
Verdict
The clearest difference is price: Codex Calc at $0.99 against RPN's $4.99. Codex Calc also leads on iOS requirement (12.0 vs 16.6). On update cadence, ads, in-app purchases 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
Codex Calc costs $0.99 and RPN $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Codex Calc ships an update every 6 months, RPN every 7 months. The most recent releases landed on June 5, 2026 and August 2, 2026 respectively.
| Parameter | Codex Calc | RPN |
|---|---|---|
| Price | $0.99 — better | $4.99 |
| Rating | 4.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 6 months — better | Every 7 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Requires iOS | 12.0 — better | 16.6 |
| Further details — not scored | ||
| Size | 11 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Driftwood Studio Software LLC | Steven Davies |
In-app purchases
Codex Calc
No in-app purchases
RPN
No in-app purchases









