Calculator

Review by eFreeware

If you regularly need trigonometry, logarithms or exponential functions on your phone, this free app from Prometheus Interactive LLC is built for exactly that. It pairs a scientific keypad with a dated record of your last 100 expressions, so the work you did earlier is still there when you come back to it. Students working through problem sets, and anyone who needs a quick graph or a fraction reduced without opening a spreadsheet, are the obvious audience.

With more than 10 million installs and a 4.4 average across 115,012 ratings, it has clearly found that audience already. The app is free, carries ads and offers in-app purchases, and it has been updated as recently as October 5, 2026, after first arriving in January 2016.

What appeals to me most is the breadth under one roof: scientific functions, everyday arithmetic, graphing, fractions and percentages all live in the same app. That range is the reason to consider it over a stripped-down calculator, and it is also the thing worth weighing carefully before you commit to it.

One keypad, several kinds of math

The core of the app is a scientific calculator that handles trigonometric, logarithmic and exponential operations. Alongside those sit the four basic operations, and the developer describes the interface as simple enough for quick day-to-day sums. In practice that means you are not choosing between a scientific tool and a basic one; the same app covers both, which is convenient when your needs shift from a tip calculation to a sine value in the same sitting.

The history panel is the feature that shapes how the app feels. It stores your last 100 expressions together with their answers and the dates they were entered, so you can look back at what produced a result instead of redoing the work. For anyone checking a long chain of calculations, that record is more useful than a single running total.

There is also a percentage mode that presents results as simple graphs. The developer pitches this at financial calculations and statistics, where seeing the proportion matters as much as the number itself. It is a small addition, but it gives the app a second life outside pure homework.

Graphing without a separate tool

The graphing side handles real-time plots and lets you define your own functions. The developer frames it as a fit for visual learners and for moments when you need a graph quickly rather than a full desktop session. That is a reasonable niche: plotting a curve to check a shape or confirm a trend is a common need, and having it in the same app as the keypad saves switching between tools.

Custom function definition is the part that adds flexibility, since it means the graph is not limited to whatever forms the app ships with. I would expect this to be most valuable to students comparing equations or checking how a change in a formula moves the curve.

What it offers is a way to see equations drawn out, which is a narrower and more honest proposition.

Fractions and percentages handled properly

Fractions get their own treatment. The app reduces them, converts between improper fractions and mixed numbers in either direction, and performs addition, subtraction, multiplication and division on them. For anyone who deals with fractions at work or in study, that conversion step is often the tedious part, so having it automated is genuinely useful.

Percentages are covered too, with results displayed as simple graphs. Financial calculations and statistics are among the uses, which makes sense for anything involving proportions, growth or share of a total.

Between the fraction tools, the percentage charts and the graphing mode, the app covers a lot of ground that would otherwise need two or three separate downloads. The trade-off is that all of it sits behind the same interface.

What you need before installing

The app is free to download, shows ads and includes in-app purchases. That combination is worth knowing up front, because it shapes what the experience is like over time.

Wear OS support is one of the more distinctive points. Being able to run calculations from a watch is a genuine convenience when your phone is not to hand, and it is not something every calculator app bothers with. If you own a Wear OS device, that alone may tip the decision.

The most recent update addresses minor bugs across several screens, makes small layout adjustments and improves general performance. Those are maintenance notes rather than new features, which suggests the app is being kept in working order rather than expanded.

Suited to students and number-heavy work

The clearest fit is anyone studying math or working with numbers regularly: students moving between basic arithmetic and scientific functions, people who need fractions reduced, and those who want a graph drawn without leaving their phone. The dated history makes it particularly practical for coursework, where you may need to retrace your steps days later.

The percentage charts and financial framing widen that slightly to include budgeting, statistics and similar work where proportions matter. And the Wear OS support means watch owners can keep the same tool on their wrist.

If your needs stop at adding up a few numbers, the scientific functions, graphing and fraction tools will go unused. The app is built for people who want the full set, and it is at its most useful when you actually reach for more than the four basic operations.

A dependable all-rounder worth installing

This is a free, well-established calculator that covers scientific functions, basic arithmetic, graphing, fractions and percentages in one place, with a dated history of your last 100 expressions and support for Wear OS. The install count and rating suggest it has settled into that role for a large number of people.

Ads are present and in-app purchases exist. If you want a completely clean, single-purpose calculator, those are factors to weigh. If you want one app that handles whatever math you throw at it, this one is built for that job.

I would recommend it to students, teachers and anyone whose work involves fractions, graphs or percentages alongside ordinary arithmetic. It is a sensible install for that group, and the free price makes trying it an easy decision.

What's new

- Addressed minor bugs across multiple screens - Minor layout improvements - General performance improvements for a smoother experience