Editor's Review
Every phone ships with a calculator, so a third-party one has to justify the space. ClevCalc does it by bundling the arithmetic you occasionally need and never remember how to do. Behind the standard keypad sit a couple of dozen separate tools: unit conversion, currency conversion with rates fetched over the network, discount and tax sums, tip splitting, fuel cost, loan repayment, date differences, unit-price comparison for supermarket shelves, body mass index and related health figures, hexadecimal and binary conversion, world time, and an Ohm's law panel for anyone wiring something up.
The main keypad keeps a scrolling history you can tap to reuse a result, handles parentheses and percentages properly, and lets you fix decimal places and thousands separators. Each sub-tool is a plain form rather than a clever interface, which is the right call: you open it, type two numbers and leave.
It is free and carries advertising, with a paid removal option, and the adverts sit around the tools instead of interrupting them. Breadth is also the weakness. The tool list is long enough that finding the one you want takes a moment, and a handful of the panels will be of use to almost nobody. Currency conversion needs a connection to refresh, and a stale rate is quietly a wrong answer. The 4.64 average across a 100M+ install base looks about right for something this useful and this unglamorous.
Features
Standard keypad with tappable history, parentheses and percentages
Unit conversion across length, weight, area, volume, speed and temperature
Currency conversion using rates fetched over the network
Discount, tax and tip calculators
Loan repayment and fuel cost estimates
Date difference and world time panels
Health figures including body mass index
Hexadecimal, binary and Ohm's law tools for technical work
Pros
Replaces a folder full of single-purpose converter apps
History makes a long chain of arithmetic easy to check
Display settings cover decimal places and separators
Advertising sits around the tools rather than blocking them
Free, with an optional paid removal of the adverts
Cons
The tool list is long enough that finding the right panel takes a moment
Currency rates need a connection to refresh, and an old rate gives a wrong answer without warning
