Integra UI vs Dúo Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Integra UI
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User interface, this feature allows engineers to create custom interfaces that can be edited by integrators and operated by on-site technicians or end users who do not understand technology. Advanced security features can only be accessed by end users within the scope permitted by the engineering contractor or system designer
Dúo Calculator
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Now compatible with iPhone Duo. LiquidCalculator is now Dúo Calculator: fold your iPhone Duo and it's a basic calculator; unfold it and it becomes a full scientific calculator. On any iPhone: a basic or scientific keypad, a unit converter and your calculation history, with a precise math engine. No ads, no account and no in-app purchases. ONE CALCULATOR, TWO SCREENS • Folded: a basic calculator with big keys. In landscape, a compact scientific keypad appears (you can turn it off in Settings). • Unfolded: a 10 × 5 scientific keypad with every function in view; with the screen flat, also programmer mode and a unit converter. • Half open like a laptop, the result sits above the fold and the keypad below it. Open like a book, the keypad splits across both sides of the fold. • Fold or unfold in the middle of a calculation and your work stays put: keys slide to their new places and the new ones appear. • It also adapts to Split View on the inner display. ON YOUR IPHONE • Pick Basic or Scientific from the menu, in portrait or landscape. • Unit converter and History on every model. • iPhone SE and accessibility text sizes keep the big basic keys. HISTORY • Your last 50 calculations, newest first • Tap a result to use it again; swipe to delete one, or clear them all • On an unfolded iPhone Duo it opens in a panel that never crosses the fold A REAL SCIENTIFIC CALCULATOR • Trigonometry in degrees or radians, inverse and hyperbolic functions • ln, log10, log2 and logarithms in any base • Powers, roots of any degree, factorial, 1/x, π, e and EE notation • Parentheses, memory (mc, m+, m−, mr) and the 2nd key • Live result as you type, plus cursor editing: tap the expression to fix any point It does not include graphing, matrices or statistics. EXACT UNDER THE HOOD Basic operations use exact fractions: 0.1 + 0.2 gives 0.3 and 1 ÷ 3 × 3 gives 1. Functions such as sin, ln or e^x are computed with 60 digits of precision and the display shows up to 16. Invalid operations, such as dividing by zero or tan 90°, show a clear error instead of a wrong answer. The engine is checked against an independent reference model on hundreds of test cases. PROGRAMMER MODE (large screens, such as an unfolded iPhone Duo) • 8, 16, 32 and 64-bit integers, signed or unsigned • BIN, OCT, DEC and HEX at once, with a bit grid you can tap • AND, OR, XOR, NOR, NOT, shifts, rotations, 1's and 2's complement, mod UNIT CONVERTER • 87 units in 11 categories: length, mass, temperature, area, volume, speed, time, data, energy, pressure and angle • Swap units with one tap, pull in the calculator's value or send the result back to it • Works offline; currencies are not included YOUR WAY • Light, dark or system theme, with optional pure OLED black • Four accent colors: amber, indigo, mint and graphite • Liquid Glass design; haptics and the aurora background are optional • Copy and paste, plus hardware keyboard support • English and Spanish, with VoiceOver labels; respects Reduce Motion, Reduce Transparency and Increase Contrast PRIVATE BY DESIGN • Collects no data: no account, no ads, no analytics, no tracking • Never uses the network: the app never sends your calculations anywhere • Settings, your last calculation and your History are stored on the device (and in its backups) and removed from it with the app COMPATIBILITY • Now compatible with and optimized for iPhone Duo, on both the outer and the inner display. • Runs on any iPhone with iOS 26 or later. Programmer mode needs a large screen, such as the inner display of iPhone Duo. • iPhone only. Support and feedback: alex@nextechia.dev iPhone and iPhone Duo are trademarks of Apple Inc. This app is independent and is not affiliated with Apple.
Screenshots
Verdict
The clearest difference is price: Integra UI at Free against Dúo Calculator's $1.99. Integra UI also leads on device support (3 vs 1) and iOS requirement (13.0 vs 26.0). On 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
Integra UI is free to download; Dúo Calculator costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Integra UI | Dúo Calculator |
|---|---|---|
| Price | Free — better | $1.99 |
| Update frequency | — | Every 6 months |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 13.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 98 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Equipson | Alejandro Hernandez Mitre |
In-app purchases
Integra UI
No in-app purchases
Dúo Calculator
No in-app purchases
Questions
Is Integra UI free?
Is Dúo Calculator free?
Do Integra UI or Dúo Calculator have ads?
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