Calca: The Most Powerful Calculation App for iPad

If an iPad is Apple’s post-PC platform of choice, it will have to be capable of completing tasks of every type. Certain activities, such as photo and video manipulation, are well-suited to the iPad’s fluid UI and direct interaction methods.

Other areas are something of a different story. For example, there is still no outstanding way to manipulate, organize, and share numerical data. The simplistic extreme of this is something like Calcbot, which makes it easy to do rather trivial mathematical operations, and then copy those to the clipboard to share via iOS’ built-in copy/paste functionality.

Calca is a step beyond this, but not quite a dedicated spreadsheet program: it leaves out most of the organization features. Instead, Calca focuses on the manipulation and sharing of data.

Like this article? Stay up to date with the latest changes by subscribing to our RSS feed or by following us either on TwitterFacebookGoogle+ or


Calca‘s main composition screen appears to be nothing more than a simple window used for text input. It draws from the minimalist school of thought that many other word processors use to present a dead-simple interface.

The main interface for Calca resembles a simple text editor, but its capabilities go far beyond that.

The main interface for Calca resembles a simple text editor, but its capabilities go far beyond that.

It works — while many other programs of this caliber drown in a deluge of confusing UI elements, Calca feels very native to iOS. Its main functionality — the ability to compute advanced mathematical equations — is hidden in its ability to detect and act upon symbols.

The user interface is also flat, so it looks particularly modern under iOS 6.


Calca includes three documents that exist to serve as a reference to showcase the vast functionality of the app.

In terms of math, Calca seems to cover all of the bases, and then some. You can create equations with multiple variables, keep track of units, hex number support, as well as various other features; the best way to see if it meets your needs is to review the documentation on the developer’s website.

Only considering the above functionality places Calca in a league all its own on iOS. But wait, there’s more!

Advanced mathematical features are found throughout Calca, and are accessed by keyboard key combinations.

Advanced mathematical features are found throughout Calca, and are accessed by keyboard combinations.

Calca makes use of Google’s extensive base of facts to extend its functionality. Are you trying to find the size/distance ratio of the sun as seen from Earth? You don’t have to know the diameter of or distance to the sun to get the answer. Simply type whatever phrase you would normally search Google with, and end the expression with the following characters: “=?”. Calca will then search Google and take the information presented — where available — and put it in your document.

When it works, it’s nothing short of magical. I can’t begin to describe how much time I’ve wasted Googling for numbers that I can’t quite remember. Now you don’t even have to leave the document to find that information.

This feature works almost all of the time, but there are times when Google doesn’t have the required information. More recently, it seems as if Google may be blocking Calca from accessing its information: I’ve seen more and more queries returned with a “Google doesn’t know” response. That’s unsettling — perhaps the developers should speak to Google, or else take their business to someone else (Wolfram|Alpha, perhaps).

Sharing, Markdown, and More

The mathematical capabilities of this program is dizzying, but it doesn’t end there. Calca also includes robust sharing and synchronization options to round out its formidable set of features.

I’ve already mentioned that Calca‘s main form of input mimics that of most high-profile text editors. It also shares another strand of DNA with apps such as iA Writer and Byword: there is Markdown support.

Markdown support is among Calca's more niche -- and therefore potentially useful -- features.

Markdown support is among Calca’s more niche — and therefore potentially useful — features.

Markdown, or a unique approach to writing HTML-compatible documents created by John Gruber, means that you can create and share documents that are already formatted and viewable by any computer or device with a web browser. It’s a fantastic inclusion, and it can also help to organize and separate information and equations in a single document.

Calca supports iOS’ built-in sharing functionality, meaning that you can send your documents by Mail. The developers could presumably also include support in the future to share your documents with other text-editing apps that could at least view your information.

Calca is also a multi-platform app: there is a Mac client. Since this app exists only on Apple platforms, it uses iCloud as the synchronization backend. It works reliably: changes to existing or new documents appear almost instantly across platforms.


So far we have an exceptional app: the feature set is sublime, the design is fantastic, and the ability to format and share your documents matches the most open apps in the App Store.

The biggest problem with Calca for iPad is something that the developers of the app have absolutely no control over: the touchscreen keyboard.

Calca's powerful feature set makes for a fantastic app that is hindered by the iPad's on-screen keyboard.

Calca’s powerful feature set makes for a fantastic app that is hindered by the iPad’s on-screen keyboard.

To perform the most complex operations that Calca is capable of, an external keyboard is almost a necessity. Inputting short formulas or equations is relatively painless, but that process becomes exceedingly difficult as length and complexity increases. My advice? Find a fantastic Bluetooth keyboard that you don’t mind carrying around when you need to use Calca on the iPad. I personally suggest the Logitech K811, though cheaper options are plentiful.


Calca is $2.99. For the price, it should be a no-brainer for anyone who ever finds themselves needing this type of app. However, as mentioned above, I would definitely recommend at least looking in to an external keyboard if you intend on using Calca‘s most powerful features.


Calca is, hands-down, the best calculation app for the iPad. If you have a need for this type of power, buy it now.