ConvertX vs Calc Engine
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ConvertX
This utility app offers comprehensive unit and currency conversion, featuring a vast library of 782 units across 56 categories. It includes popular and rare units, a powerful search function, and a favorites list for quick access. Real-time currency exchange rates are also provided.
- 782 units in 56 categories
- Popular and rare unit support
- Powerful search functionality
- Favorites for quick access
- Real-time currency exchange rates
- In-built calculator
- Customizable themes
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Units & currency converter covering first ever 782 units in 56 categories AppAdvice.com: Rating - 5 star "ConvertX is one of the most convenient and useful conversion apps I’ve seen out there, and for $.99, this is a must have." - AppAdvice.com TheiPhoneappreview.com: Rating - 4.5/5 "The huge selection of units to convert to and from, the excellent layout and the simplicity of use is truly impressive, making Convertx one of the best converter apps on the market today" - TheiPhoneappreview.com Popular & Rare Categories Popular categories like Length, Mass, Volume, Area to rare categories like Capacitance, Illuminance, Inductance, Moment of Inertia covered. Search Powerful search to access every category/unit instantly. Favorites Frequently used units can be added to favorites and can be accessed quickly. No more searching of frequently used units. Large Forex Currencies including US Dollar, British Pound, Canadian Dollar, Australian Dollar, Euro, Swiss Franc, Japanese Yen. Updated several times daily*. Convenience In-Built calculator for quick use. The themes are now available for free. Add More Additional categories or units can be added on popular request. *Need internet for update
Calc Engine
A highly customizable calculator with advanced features like graphing, equation solving, and unit conversion. Design your own keyboards and functions to streamline your workflow across Apple devices.
- Customizable keyboard layouts
- User-defined functions and constants
- Live equation graphing
- Equation solving
- Extensive unit conversions
- Programmer mode (hex, binary, octal)
- Cross-device syncing
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Calc Engine™ — The Calculator That Fits How You Work Whether you're splitting a dinner bill, plotting an equation, or working through bitwise logic, Calc Engine meets you where you are. It's a beautiful, fully customizable calculator that grows with you — and syncs seamlessly across iPhone, iPad, Mac, and Apple Watch. Make it look and feel like yours • Choose from rich color themes to match your style • Pick the fonts and key shapes that feel right in your hands • A calculator you actually enjoy opening Design keyboards your way • Build your own keyboard pages — drag any key from a curated library onto a 4×5, 5×5, or 6×5 grid • Mix digits, operators, scientific functions, your own constants — anything you reach for often, all in one place • Set a long-press alternate on any key so a single tile handles a primary and secondary action • Name each keyboard, pick its icon, and reorder it alongside the standard pages — your custom keyboards show up right where you'd expect them • Enable or disable any page (built-in or custom) per device Build your personal math library • Define your own functions with up to three parameters — name them whatever makes sense to you • Save the constants you use all the time and insert them with a single tap • Full calculation history, automatically saved — scroll back anytime Powerful math, always within reach • Trig (radians or degrees), logarithms, exponentials, roots, and more — there when you need them, out of the way when you don't • Live results as you type, so you always know where you're headed • Per-function rounding built in — perfect for money, measurements, or anything that needs a clean output Convert between hundreds of units in seconds • Tap a value, then any two units to see the conversion live — miles to km, lb to kg, °F to °C, gal to L, anything you need • 250+ built-in units across 40+ categories: length, mass, volume, temperature, time, speed, angle, energy, power, pressure, electrical, magnetic, optical, radioactivity, data, and more • Favorite the categories you actually use so they sit at the top — synced across your devices automatically • Build your own functions with conversions baked in — define a formula once and reuse it forever See your equations come to life in graphs • Plot equations like x = y² or sin(x) live as you type, right beside the keyboard • Tap any graph to expand into a full-screen view for closer inspection • A dedicated graphing keyboard with x, y, and = keeps everything in one place — no separate app, no separate mode Solve equations as you type • Type x² = 121 or sin(x) = 0.5 and Calc Engine finds every real answer • Tap the solved answers to reuse it in your next calculation, no separate "solve" mode Programmer mode without leaving the calculator • Type hex (0x), binary (0b), and octal (0o) literals — read and write the way you read code • A full bitwise toolkit: AND, OR, XOR, NOT, shifts, and rotates • Every result shown in HEX, DEC, OCT, and BIN simultaneously, with configurable word size (8/16/32/64) and signed/unsigned interpretation • Tap the binary row to expand into a byte-by-byte view with bit-position labels Private by design • Everything syncs through your personal iCloud — nothing stored on our servers • Fully localized and native on every Apple platform Unlock Calc Engine+ for the full experience — custom themes, fonts, key shapes, custom keyboards, user-defined functions, saved constants, unit conversions, live graphing, equation solving, programmer-mode hex/binary/bitwise, and more. Everything that makes Calc Engine truly yours. Teach it your formulas once. Customize it to feel like home. Use it forever.
Screenshots
Verdict
The clearest difference is update cadence: Calc Engine at daily against ConvertX's every 9 months. Calc Engine also leads on ratings volume (4 vs 1) and device support (4 vs 2). ConvertX's advantage is iOS requirement (11.0 vs 18). On price, rating, 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
Both are free to download. ConvertX sells 3 one-off in-app purchases and Calc Engine sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 5.0 for ConvertX against 5.0 for Calc Engine. Both are backed by a comparable volume of ratings — 1 and 4 respectively.
ConvertX ships an update every 9 months, Calc Engine daily. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.
| Parameter | ConvertX | Calc Engine |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (4 ratings) |
| Positive reviews | 70.8% of reviews | — |
| Number of ratings | 1 | 4 — better |
| Update frequency | Every 9 months | Daily — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, Mac, Apple Watch — better |
| Requires iOS | 11.0 — better | 18 |
| Further details — not scored | ||
| Size | 19 MB | 17 MB |
| Age rating | 4+ | 4+ |
| Developer | Mallow Technologies Private Limited | VersaEdge Software, LLC |
Customer experience
ConvertX
Calc Engine
In-app purchases
ConvertX
- GoodFree
- Excellent!Free
- Wow!!Free
Calc Engine
- Calc Engine+$9.99









