How to Use Two Calculators at Once on an iPhone

Why there's no built-in way

iPhone has never supported side-by-side app multitasking — one app owns the screen (Split View is iPad-only). And even where Split View exists, iPadOS won't open two instances of the same calculator app. So "two calculators at once" has to come from a single app that provides multiple calculators itself.

Option 1: A multi-panel calculator app (the real fix)

Several apps put two or more independent calculators on one screen:

• CalcBoard (our app): 2 panels free / up to 8 with a one-time $2.99 purchase; each panel can be a basic, scientific, programmer, or unit-converter calculator; a shared tray and named variables move values between panels; no ads.
• DualCalc, Twin-Calc, and similar: two fixed calculators stacked on one screen. Simple and focused; typically limited to two basic panels.
• MultiCalc and Multiple Calculators: several nameable basic calculators at once, closer to a list of tapes than a mixed-mode workspace.

If you only ever need two basic calculators, a dual-calculator app is enough. If your second calculator is ever a converter, a scientific keypad, or a hex view — or you want the two sides to exchange results — you want a multi-panel app with modes.

Option 2: Calculator app + Math Notes

On iOS 18+, Apple's Calculator includes Math Notes, which evaluates expressions inside a note. You can keep the Calculator open for one problem and a Math Note for another and switch between them. It's genuinely useful for written-out problems, but it's still one screen at a time — you're switching, not seeing both.

Option 3: The web-tab workaround

Open a web calculator in Safari and use the app switcher to bounce between it and the Calculator app. Zero cost, works today, and shares the core flaw: only one calculation is ever visible, and iPhone Safari + app switching is slower than either calculation.

What to pick

Frequently Asked Questions