Comparison

x36 vs HP16C

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

Head to head
About

x36

This app offers a powerful scientific and engineering calculator with advanced features like programmability, multiple number bases, and statistical functions. It emulates the functionality of calculators from the 70s and 80s, providing over 100 functions for complex calculations.

Highlights
  • Programmability with 1000 steps
  • Trigonometric functions with selectable units
  • Statistical functions and linear regression
  • Four number bases (Decimal, Hex, Octal, Binary)
  • Metric-English conversions
  • Fraction operations
  • Over 100 functions
Features
Read full description

This calculator is packed with features common to any good scientific and engineering calculator from the 70's and 80's including: Programability. Can store up to 1000 steps. Includes label, jump, loop and subroutine capability. -Common mathematical operations including square roots, powers, reciprocals, and logarithmic functions. -Up to 15 levels of parenthesis. -A full set of trigonometric functions working with user selectable units of degrees, radians, and gradians. Also performs polar-rectangular and degrees-minutes-seconds - decimal degree conversions. -Common physical constants such as the speed of light, gravitational constant and Avogadro's number. -Single and double variable statistical functions including linear regression. 10 memory storage locations. -Metric-English and English metric conversions. -Four number bases (Decimal, Hexadecimal, Octal, and Binary). -Bit logic operations. -Three display modes (floating point, scientific, and engineering) with user adjustable number of digits displayed. -Can perform operations with fractions! Over 100 functions in all! AND NO ADS!

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

x364 screens
HP16C4 screens

Verdict

The call

The clearest difference is price: HP16C at Free against x36's $0.99. HP16C also leads on update cadence (every 8 days vs every 2 months). x36's advantage is iOS requirement (12.0 vs 17.0). On rating, ratings volume, ads and in-app purchases 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; x36 costs $0.99 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 — 5.0 for x36 against 5.0 for HP16C. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

UpkeepUpdate frequency

x36 ships an update every 2 months, HP16C every 8 days. The most recent releases landed on September 22, 2026 and September 21, 2026 respectively.

Scorecard4 real differences · 6 level
x36 versus HP16C: the parameters behind the verdict, then further details
Parameterx36HP16C
Price$0.99Free — better
Rating5.0 (1 ratings)5.0 (2 ratings)
Positive reviews100.0% of reviews—
Number of ratings12 — better
Update frequencyEvery 2 monthsEvery 8 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS12.0 — better17.0
Further details — not scored
Size1 MB1 MB
Age rating4+4+
DeveloperCarl CookMichael Doornbos

In-app purchases

None

x36

No in-app purchases

None

HP16C

No in-app purchases

Questions

Is x36 free?
x36 costs $0.99, with no in-app purchases.
Is HP16C free?
HP16C is free to download, with no in-app purchases.
Which has better reviews, x36 or HP16C?
x36 and HP16C are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.
Do x36 or HP16C have ads?
Neither x36 nor HP16C shows ads.
Which is updated more often, x36 or HP16C?
x36 ships an update every 2 months, and HP16C every 8 days. Most recently, x36 was updated on September 22, 2026 and HP16C on September 21, 2026.

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