RPN vs DB48X
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
DB48X
This advanced scientific calculator offers arbitrary precision computations, RPN and algebraic operations, and extensive graphing capabilities. It supports complex numbers, matrices, symbolic calculations, and over 1000 built-in functions, inspired by the HP48 series.
- Arbitrary precision computations
- RPN and algebraic operations
- Complex numbers, vectors, and matrices
- Symbolic computations and numerical solving
- Graphing and plotting
- Engineering units and currency conversion
- Built-in hyperlinked help system
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DB48X is a new high-precision scientific calculator inspired by the legendary HP48 series from Hewlett-Packard. It is not an emulator, but a redesign from scratch, which is faster, and delivers never seen before capabilities like computations in arbitrary precision. Like the original HP48, DB48X supports an unlimited stack, RPN and algebraic operations, complex numbers, based numbers, vectors, matrices, text, symbolic computations, numerical solving and integration, graphing and plotting, statistics, engineering units, and well over 1000 built-in functions. DB48X adds several HP50G capabilities, including a library of equations and constants covering mathematics, physics or chemistry. Using modern technologies, DB48X goes well beyond the original HP48 in many ways: - It is significantly faster, uses less memory, and features a higher-resolution 240x400 pixels graphical display. - Integer and decimal values can have an arbitrarily large number of digits, so you can compute log(pi) with 200 digits in a few keystrokes. - The six function keys feature up to three function per key, giving quick access to up to 18 related functions at a time. - Complex numbers can mix and match polar and rectangular form. - Symbolic operations extend to complex numbers, vectors and matrices. - Based numbers can be in any base from 2 to 36, and support any number of bits, making it easy to emulate a 23-bit or 512-bit processor. - Text is represented using Unicode instead of the proprietary HP encoding, facilitating data exchange with the rest of the world. - Multiple graphs can be distinguished using bitmap patterns (DB50X adds the ability to use colors) - Engineering units include all the modern evolutions of the SI system, and can be configured by the user, e.g. to integrate currency units with the exchange rate du jour. Converting between USD/hour and EUR/day has never been so easy! - A built-in hyperlinked help system documents functions simply by holding the corresponding key, and combine a quick start guide, a user manual and a reference manual. DB48X will run many user RPL programs as is. However, since it is not an emulator, it will not run any HP binary object, and notably will not run HP48 games or anything involving system RPL. DB48X is part of a family of compatible RPL calculators that include the free DB40X and the color DB50X.
Screenshots
Verdict
The clearest difference is update cadence: DB48X at every 3 weeks against RPN's every 6 months. DB48X also leads on review sentiment (100% vs 71%) and rating (4.8 vs 4.4). RPN's advantage is price ($1.99 vs $4.99) and chart position (#184 vs unranked). 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 DB48X $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.
DB48X holds the better App Store score, 4.8 against 4.4. Both are backed by a comparable volume of ratings — 14 and 4 respectively. Written reviews point the same way: 71% of RPN's written reviews are positive against 100% of DB48X's.
RPN ships an update every 6 months, DB48X every 3 weeks. The most recent releases landed on September 6, 2026 and September 10, 2026 respectively.
| Parameter | RPN | DB48X |
|---|---|---|
| Price | $1.99 — better | $4.99 |
| Rating | 4.4 (14 ratings) | 4.8 (4 ratings) — better |
| Positive reviews | 71.4% of reviews | 100.0% of reviews — better |
| Number of ratings | 14 — better | 4 |
| Update frequency | Every 6 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Best chart rank | #184 — better | — |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 — better | 14.0 |
| Further details — not scored | ||
| Size | 14 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | CuVee Software | Christophe de Dinechin |
Customer experience
RPN
DB48X
In-app purchases
RPN
No in-app purchases
DB48X
No in-app purchases








