PocketEngineer

A classic RPN calculator, handcrafted the old way. PocketEngineer works like the legendary HP pocket calculators: a four-register stack (X, Y, Z, T), Enter instead of equals, and every keystroke exactly where your thumbs expect it. Built by an engineer who has used RPN for forty years — first in C++, now ported by hand to Swift. WHAT MAKES IT DIFFERENT • Date & duration arithmetic — subtract two dates and get days and hours, add 90 minutes to a timestamp, count the days until Christmas. Time math is a first-class citizen, not an afterthought. • The Tape — a paper-tape history of every calculation. Tap any line to rewind the stack to that exact point. The tape never lies: even rewinds are logged. • Real RPN — 4-register stack, Swap, Roll, Drop, stack always visible. • Scientific board in landscape — trig, logs, powers, constants. Portrait stays a clean, plain calculator. • 10 memory registers, persistent between launches. • Hardware keyboard support on iPad. HONEST SOFTWARE Free forever. No ads, no tracking, no accounts, nothing locked. If you enjoy it, there is a small tip jar behind the info button — that's all. Handcrafted by M. Biermaier.