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Calculator apps you buy once.

Buy GraphNCalc83. It is the highest-rated calculator on the store, it lays out exactly like the TI-83 you already know, and it is quicker than the hardware. Tydlig is the interesting one — it drops the keypad for a canvas where numbers stay linked — and it costs almost nothing. The two from Incpt.Mobis are the safe, widely owned picks: one for graphing, one for scientific work.

The filter. Every app here is a single purchase. None of them can start charging you monthly for what you already bought. See every app under this rule ›
Top pick

GraphNCalc83

Ernest Brock
View on the App Store ›
$12.99 once4.9★ (4,037)Updated Nov 22, 2025
Verdict
The best-liked calculator on the App Store and it earns it. A TI-83 layout you already know, running far faster than the plastic one ever did.
Best for
A student or engineer who thinks in TI keystrokes and wants them without the hardware.
The catch
It is a graphing calculator and nothing else — no tape, no unit conversion, none of the everyday conveniences — and no exam hall will let you bring a phone, which is where most people actually need a TI-83.
One-time purchaseTI-83 layoutGraphing

Tydlig

Tydlig Software AB
View on the App Store ›
$1.99 once4.8★ (2,627)Updated Nov 28, 2017
Verdict
Throws out the keypad entirely. Numbers sit on an endless canvas, stay connected to each other, and update everything downstream when you change one.
Best for
Anyone doing the kind of arithmetic where you keep changing an input and want to watch the answer move.
The catch
You have to unlearn a calculator to use it, and a crash reviewers have been reporting since iOS 11 still turns up in recent reviews.
One-time purchaseNo subscriptionLinked numbers

Graphing Calculator Plus AI

Incpt.Mobis
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$5.99 once4.6★ (12,029)Updated Feb 26, 2026
Verdict
The one most people end up owning. Broad, capable, and priced low enough that it is the default recommendation in a lot of classrooms.
Best for
Someone who needs a graphing calculator today and does not want to research it.
The catch
It looks its age and people say so — the interface draws as many complaints as compliments, and several reviewers say it took real effort before it clicked.
One-time purchaseGraphingWidely used

Calculator ∞

Incpt.Mobis
View on the App Store ›
$5.99 once4.7★ (6,344)Updated Mar 12, 2026
Verdict
The scientific counterpart to the one above, from the same developer, and the better buy if you want a calculator rather than a plotter.
Best for
Someone who wants a fuller scientific keypad than the built-in app offers.
The catch
The Mac version does not take keyboard input, which makes it close to unusable there, and reviewers report updates breaking things that previously worked.
One-time purchaseScientificiPhone and iPad

Side by side.

AppPriceTypeKeypadMade forUpdated
GraphNCalc83$12.99GraphingTI-83 layoutTI usersNov 22, 2025
Tydlig$1.99ScientificCanvas, no keypadChanging inputsNov 28, 2017
Graphing Calculator Plus AI$5.99GraphingStandardClassroomsFeb 26, 2026
Calculator ∞$5.99ScientificStandardEveryday mathsMar 12, 2026

Who should skip this entirely.

Apple's own Calculator now does scientific mode, unit conversion and a running history, and it is free on every device you own. If that covers you, stop here. And if the reason you want one is an exam, none of these help — a phone is not allowed in the room, so you need the physical calculator regardless of what it costs.

Questions.

Will any of these get me through an exam?No. Exams that allow a graphing calculator do not allow a phone, so you still need the hardware. These are for the other ninety per cent of the time.
Two of these are by the same developer — why both?They are genuinely different products: one plots, one is a scientific keypad. If you only want one, pick by which of those you actually do.