Comparison

Halcyon Calc vs HP16C

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

Head to head
About

Halcyon Calc

A powerful calculator app for students, engineers, and scientists. It handles complex numbers, symbolic expressions, unit conversions, and matrix operations, with advanced plotting and programming capabilities.

Highlights
  • Complex number calculations
  • Symbolic expression manipulation
  • Unit conversion with custom units
  • Matrix and vector operations
  • Symbolic plotting
  • Programming of custom operations
  • Statistical data analysis
Features
Read full description

For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc is a great application for manipulating numbers and even symbolic expressions. Features: - Use this calculator on an iPhone, iPod Touch or an iPad - Use your finger to quickly scroll through the stack to review intermediate results - Copy and paste support - Over 225 built-in operations, including trig, logarithms, real functions, complex operations and more - Allows you to work with real, complex and integer numbers. - Real and complex numbers can be displayed in standard, fixed, scientific and engineering format - Use over 120 built-in units to perform unit conversion or create your own units if the one you want is not already there - Integer numbers can be displayed in decimal, hexadecimal, octal and binary bases - Work with real and complex matrices and vectors. - Enter symbolic expressions and solve them for different values. Even better, solve quadratic formulas, collect and expand factors and terms, find minima, maxima and roots of any expression. - Plot symbolic expressions in X/Y coordinates. Pan the coordinate space by dragging the plot in any direction. Zoom in and out using a pinch gesture. - Determine symbolic derivative, taylor series or numeric integral of an expression. - Store numbers, lists, strings and expressions in symbols. Create hierarchies of symbols to allow you to organize your calculations. - Create sequences of calculator commands into programs, creating your own operations which you can then include in expressions. - Store statistical data and calculate totals, averages, standard deviations, linear regressions, etc over that data. - Calculate the probabilities associated with standard distributions like the normal, F and T distributions.

About

HP16C

This app faithfully recreates the legendary HP 16C Computer Scientist calculator, offering advanced hex arithmetic, bit manipulation, and base conversion. It features RPN, keystroke programming, and modern enhancements like a two-line display and haptic feedback.

Highlights
  • Full RPN calculator
  • Integer arithmetic (HEX, DEC, OCT, BIN)
  • Configurable word size (1-64 bits)
  • Complete bit operations
  • Keystroke programming
  • Two-line display
  • Haptic feedback
Features
Read full description

A faithful recreation of the legendary HP 16C Computer Scientist calculator for iPhone, with a few modern upgrades. If you've ever needed to perform hex arithmetic, bit manipulation, or base conversion on your phone and been frustrated by the available options, this is for you. RPN-16C gives you the full power of the original HP 16C in your pocket. WHAT IT DOES - Full RPN (Reverse Polish Notation) calculator - Integer arithmetic in HEX, DEC, OCT, and BIN - Configurable word size from 1 to 64 bits - Unsigned, one's complement, and two's complement modes - Complete bit operations: shift, rotate, rotate through carry, AND, OR, XOR, NOT, mask, bit set/clear/test, count bits, left justify - Float mode with configurable precision (FLOAT 0-9) - Keystroke programming with labels, subroutines, loops, and conditionals - Storage registers with direct and indirect addressing - Programs can be imported from text (long-press the display to paste) ENHANCEMENTS OVER THE ORIGINAL - Two-line display: see both X and Y registers at once. No more guessing what's on the stack. - Wider LCD: displays all 32 bits in binary without scrolling. The original could only show 8 at a time. - Haptic feedback on every key press - State persistence: pick up right where you left off - SHOW function to peek at values in other bases FAIR WARNING This is a quirky calculator. It uses Reverse Polish Notation, has no equals key, and expects you to know what two's complement means. If you're looking for a simple calculator, this is not it. If you've ever wished you could do a bitwise rotate through carry on your phone, welcome home. DESIGNED FOR PROGRAMMERS The key layout matches the physical HP 16C exactly, including the f (gold) and g (blue) shift labels. If you know the original, you already know this one. The original HP 16C Owner's Handbook is freely available on the Internet Archive: https://archive.org/details/hp-16c_handbook

Screenshots

Halcyon Calc4 screens
HP16C4 screens

Verdict

The call

The clearest difference is price: HP16C at Free against Halcyon Calc's $4.99. HP16C also leads on update cadence (every 8 days vs every 4 months). Halcyon Calc's advantage is ratings volume (18 vs 2). On rating, 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

CostPrice · In-app purchases · Ads · Monetization

HP16C is free to download; Halcyon Calc costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for Halcyon Calc against 5.0 for HP16C. That said, the two scores are not equally well evidenced: Halcyon Calc has 18 ratings behind it against 2, so its average is the more settled of the two.

UpkeepUpdate frequency

Halcyon Calc ships an update every 4 months, HP16C every 8 days. The most recent releases landed on September 22, 2026 and September 21, 2026 respectively.

Scorecard4 real differences · 6 level
Halcyon Calc versus HP16C: the parameters behind the verdict, then further details
ParameterHalcyon CalcHP16C
Price$4.99Free — better
Rating4.9 (18 ratings)5.0 (2 ratings) — better
Positive reviews100.0% of reviews—
Number of ratings18 — better2
Update frequencyEvery 4 monthsEvery 8 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad
Requires iOS16.6 — better17.0
Further details — not scored
Size10 MB1 MB
Age rating4+4+
DeveloperHalcyon Touch SoftwareMichael Doornbos

In-app purchases

None

Halcyon Calc

No in-app purchases

None

HP16C

No in-app purchases

Questions

Is Halcyon Calc free?
Halcyon Calc costs $4.99, with no in-app purchases.
Is HP16C free?
HP16C is free to download, with no in-app purchases.
Which has better reviews, Halcyon Calc or HP16C?
HP16C is rated higher. Halcyon Calc averages 4.9 out of 5 from 18 ratings, while HP16C averages 5.0 from 2 ratings.
Do Halcyon Calc or HP16C have ads?
Neither Halcyon Calc nor HP16C shows ads.
Which is updated more often, Halcyon Calc or HP16C?
Halcyon Calc ships an update every 4 months, and HP16C every 8 days. Most recently, Halcyon Calc was updated on September 22, 2026 and HP16C on September 21, 2026.

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