Comparison

RPN 28x Calc vs MathNotes

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

RPN 28x Calc

A programmable scientific calculator offering a classic aesthetic with modern functionality. It features a dynamic stack display, customizable buttons, and support for multiple data types, making complex calculations intuitive and accessible.

Highlights
  • Reverse Polish Notation (RPN) input
  • Dynamic stack display with scrolling
  • Customizable buttons and programming
  • Support for multiple data types (real, complex, binary, lists, etc.)
  • 147 scientific units and physical constants
  • Interactive program debugging
  • Units and log viewers
Features
Read full description

RPN 28x Calc is a programmable scientific calculator with a pleasingly classic look. Despite its nostalgic appearance, it offers a modern and intuitive user experience, allowing you to interact with your operands by touching them in the display. It is a reverse-polish notation (RPN) calculator with a dynamic stack display. As you add more values to the stack, the display shown on an iPad automatically expands. To see more lines, simply swipe to scroll. You can also re-order the levels or modify any of the values on the stack. ----- "It’s the third RPN calculator I buy for my iPad 2 and the first that makes me happy. It’s graphically appealing, intuitive and very responsive. I rated it 5 stars." (Nuno Gomes) ----- Advanced commands are available in a secondary panel on iPad or as alternative button pages on iPhone. The buttons are efficiently grouped into five pages that you can quickly access by swiping left or right: - user-defined buttons, - letters A-Z for typing, - trigonometric, logarithmic, and data manipulation commands, - statistics, storage and programming commands - binary integers, system flags and boolean logic. This is why RPN 28x Calc is unique in its class: - You can tap a row to select it and issue commands for the selected level. - In REORD mode, it is possible to rearrange the stack by dragging the rows. - You can swipe up or down the display to see all levels. - When you enter a value, you can tap a digit to reposition the cursor. - Tap on the status indicators in the top of the display to change their state. - Drag buttons to re-arrange them as you like it (enable that in the settings). Additionally, on iPad: - The display automatically resizes to show more than just 4 levels of the stack. - You can slide the secondary panel out of view or swipe across the panel to navigate between button pages. New: - 147 scientific units and elementary physical constants. - Upper-tail probablity distribution commands. - Interactive program debugging. RPN 28x Calc is all you need. - High precision arithmetics. - Supports multiple data types: real numbers, complex numbers, binary integers, or lists, arrays, vectors, matrices, programs, names, and strings. - Name your own variables; inspect them in the variable viewer. - Use the rich command set to write your own programs. - Create buttons for your programs. - Interactive button reordering. - Browse all scientific units and constants in the units viewer. - View the command history and the results in the log viewer. - Customizable button click & alert volumes. - Support for landscape orientation. - Optional thousand separators. - Haptic feedback on iPhone. - External keyboard support. - Dark Appearance since iPadOS 13 or iOS 13. - Alternative, dark app icon. - Use the same app on iPad or iPhone. - Use the calculator in iPad multitasking, i.e. in a Slide Over view or in Split View. - No ads, no tracking, and no rating requests. - Downloadable user guide with introduction and command reference (PDF). ----- Plans for future versions (NOT YET SUPPORTED): - Arithmetic expressions.

About

MathNotes

This app offers a comprehensive suite for STEM students, combining handwritten note-taking with powerful math solving capabilities. It features an AI tutor, graphing tools, and specialized calculators, all designed to aid in learning and organization. Notes can be compiled into professional documents and exported as PDFs.

Highlights
  • Handwritten note-taking with Apple Pencil
  • Photo-based math problem solver
  • 12 specialized calculators
  • AI tutor for homework help
  • PDF import and annotation
  • Offline functionality
  • Export to formatted PDFs
Features
Read full description

The all-in-one math solver and study app. MathNotes combines Desmos-like graphing, Symbolab-like step-by-step solving, 12 specialized calculators, an AI tutor, and beautiful handwritten notes, all in one place. Write naturally - Handwrite with Apple Pencil or your finger, no keyboard needed - Keep notes handwritten or compile to publication-ready documents Solve anything - Snap a photo of any problem for instant solutions, graphs, and step-by-step explanations - 12 built-in calculators: graphing, scientific, matrix, symbolic, unit converter, and more - AI-powered help that actually understands your work Stay organized - Unlimited notebooks and folders - Tag definitions, theorems, and formulas to build your own knowledge base - Import, annotate, and markup PDFs and textbooks - Export beautiful, perfectly formatted PDFs Built for students - Privacy-first: your notes are encrypted and never used for AI training - Works offline - One app replaces Desmos, Symbolab, Photomath, and your note-taking app Subscription - Plus unlocks unlimited notes, cloud sync, and other basic features. Premium unlocks the AI chat, agentic LaTeX editor, and cloud sync. Everything else: notes, all 12 calculators, PDF support: is free with limited use. Try Premium free for 7 days! Terms of Use: https://mathnotes.io/terms Privacy Policy: https://mathnotes.io/privacy

Screenshots

RPN 28x Calc4 screens
MathNotes4 screens

Verdict

The call

The clearest difference is price: MathNotes at Free against RPN 28x Calc's $6.99. MathNotes also leads on update cadence (every 4 days vs every 2 months). RPN 28x Calc's advantage is in-app purchases (none vs 8) and ratings volume (34 vs 2). On rating, review sentiment, ads 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

CostPrice · In-app purchases · Ads · Monetization

MathNotes is free to download; RPN 28x Calc costs $6.99 up front. MathNotes sells 8 in-app purchases, starting at $1.99 per month. RPN 28x Calc asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for RPN 28x Calc against 5.0 for MathNotes. That said, the two scores are not equally well evidenced: RPN 28x Calc has 34 ratings behind it against 2, so its average is the more settled of the two. Written reviews are what separate them: 97% of RPN 28x Calc's written reviews are positive against 100% of MathNotes's.

UpkeepUpdate frequency

RPN 28x Calc ships an update every 2 months, MathNotes every 4 days. The most recent releases landed on September 13, 2026 and August 24, 2026 respectively.

Scorecard6 real differences · 4 level
RPN 28x Calc versus MathNotes: the parameters behind the verdict, then further details
ParameterRPN 28x CalcMathNotes
Price$6.99Free — better
Rating5.0 (34 ratings)5.0 (2 ratings)
Positive reviews96.7% of reviews100.0% of reviews — better
Number of ratings34 — better2
Update frequencyEvery 2 monthsEvery 4 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.4 — better15.1
Further details — not scored
Size3 MB181 MB
Age rating4+4+
Developertredje designMark Miller

Customer experience

RPN 28x Calc

All ratings34 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews30 reviews
Positive96.7%
Neutral0.0%
Negative3.3%

MathNotes

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

RPN 28x Calc

No in-app purchases

8 purchases

MathNotes

Subscriptions5
  • iwrote Plus7 Days trial$1.991 Month
  • MathNotes Premium7 Days trial$9.991 Month
  • MathNotes Pro7 Days trial$9.991 Month
Show 2 more
  • MathNotes Plus7 Days trial$19.991 Year
  • MathNotes Pro7 Days trial$99.991 Year
One-time3
  • 1 Course Credit$24.99
  • 3 MathNotes Credits$54.99
  • 5 MathNotes Credits$74.99

Questions

Is RPN 28x Calc free?
RPN 28x Calc costs $6.99, with no in-app purchases.
Is MathNotes free?
MathNotes is free to download, with in-app purchases available.
Which has better reviews, RPN 28x Calc or MathNotes?
RPN 28x Calc and MathNotes are both rated 5.0 out of 5 on the App Store, from 34 and 2 ratings respectively.
Do RPN 28x Calc or MathNotes have ads?
Neither RPN 28x Calc nor MathNotes shows ads.
Which is updated more often, RPN 28x Calc or MathNotes?
RPN 28x Calc ships an update every 2 months, and MathNotes every 4 days. Most recently, RPN 28x Calc was updated on September 13, 2026 and MathNotes on August 24, 2026.

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