Soulver

Soulver is the Mac and iOS calculator notepad built by Acqualia, an Australian indie app studio, launched in 2005. It solves a specific pain: real-world calculations involve context and words ("hotel for 3 nights at $180 / night = ?") that a regular calculator can't handle, but Excel is overkill and error-prone for quick scratch pad math. Soulver lets you write natural language calculations line by line, with the answer displayed on the right — a scratchpad that actually calculates. Soulver grew to $1M+ ARR as a one-person project (later small team) by becoming the default recommendation in "essential Mac apps" lists among developers, accountants, consultants, and anyone who does quick calculations regularly. Features like currency conversion (live rates), percentage shortcuts (200 + 15%), and the ability to reference previous lines ("total * 0.2 for VAT") made it genuinely useful for budgeting, travel expense calculation, and project estimation. The app's longevity — 20 years of active development — demonstrates that a focused, useful tool can sustain a small business indefinitely.