# Calculator ft+ — Construction RPN · RPL · CAS > Dual-mode calculator for construction and RPL computing with extensive educational resources. (iPhone/iPad app by Marcelo Mejia Cobo.) - Source: https://appshunter.io/ios/app/calculator-ft-plus/id6804355721 (this page in markdown: same URL + `.md`) - Developer: [Marcelo Mejia Cobo](https://appshunter.io/developer/365496933) - Category: Utilities, Productivity - Price: $5.99 - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 13.0 · 66 MB - Languages: American English - Released: 2026-09-08 - Data updated: 2026-09-12 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/calculator-ft-plus/id6804355721/reviews.md ## What is Calculator ft+? Calculator ft+ is two machines on one screen. THE CONSTRUCTION CALCULATOR An RPN calculator with a real dimensional engine. Enter 5.5 m + 6.5 ft and get 7.4812 m — the first unit you enter wins, and every value converts live to km, m, cm, mm, ft, in, yd, mile and nautical mile while a tape-measure readout shows feet, inches and 64ths. Multiply two lengths and you get a true area; take the square root of an area and you are back to a length. Mass times gravity reads in newtons. Type "5 ft 3 1/4 in" — or say it out loud — and it lands as a real length. Press-hold any value to edit it on a construction keyboard with every unit, constant and tape fraction. THE RPL COMPUTER Flip the FT|RPL switch and the same screen becomes an RPL machine in the spirit of the great HP handhelds, powered by the open-source newRPL engine: an unlimited typed object stack (reals at 32-digit precision, lists, unit objects, programs, algebraics), soft menus, programs you can store under a name and run from the VAR menu, engine-sampled function plotting, and a symbolic CAS that expands, differentiates and solves. A full RPL workspace is one tap away in Settings — same engine, same memory. BUILT TO TEACH A hundred and ninety worked examples ship inside, searchable and filterable — from rafter lengths and stair risers to beam deflection, Reynolds numbers and voltage drop, plus a twenty-program RPL course, a ten-graph plotting workbook, and the whole HP equation library in 86 programs — optics, oscillations, magnetism, waves, motion, forces, electricity, gases, heat transfer, columns and beams, stress, fluids and solid state devices. Each is solved keystroke by keystroke — every key drawn as its own chip, ringed on a screenshot of the calculator — and carries a formula card you can copy: the equation as written on paper, the one-line RPL that runs it, the program's source ready to paste and run, and what every symbol means. Ninety-one also carry a lettered reference diagram. One tap stores any example program under its name. Export your programs as plain-text modules, load modules from the clipboard, and read the full 27-chapter illustrated field manual in English or Spanish. ALSO IN THE BOX • 18 unit-aware memory slots and an unlimited history stack, all persistent • A help feed that narrates every step — sessions export to PDF • Customizable prime keys and a drag-to-reorder unit column • Voice and typed requests, on-device • 42 physical constants as real unit quantities, and 267 soft-menu commands • The nine-row converter works for any quantity — type 50 kg and read grams, tonnes, pounds, ounces, slugs and grains • On iPad the example pages run two columns with the screenshot pinned • Runs on iPhone and iPad Calculator ft+ contains open-source software: newRPL (BSD 3-clause), SymEngine (MIT) and portions of Boost (BSL-1.0). Licenses are reproduced in the app. ## Key features - Unit-aware dimensional engine - Live unit conversion - RPN and RPL modes - Symbolic CAS - Extensive worked examples - Programmable functions - Unit converter ## Frequently asked questions about Calculator ft+ ### What is Calculator ft+? Calculator ft+ is a powerful utility app that functions as both a construction calculator with dimensional analysis and an RPL computer. It offers advanced features for unit conversion, programming, and symbolic calculations. ### What kind of calculations can Calculator ft+ perform? It can perform dimensional calculations with live unit conversions across various units (meters, feet, inches, etc.), mass and gravity calculations, and area/length conversions. The RPL mode supports advanced math, programming, and symbolic CAS operations. ### Does Calculator ft+ have educational content? Yes, Calculator ft+ includes 190 worked examples covering topics from construction to physics, a 20-program RPL course, and a plotting workbook. Each example is explained keystroke by keystroke with formula cards. ### What platforms does Calculator ft+ support? Calculator ft+ is available for iPhone and iPad, offering a dual-column view on iPad for enhanced usability. ### How does Calculator ft+ handle units? It features a real dimensional engine that understands units, converting them live as you input them. It supports a wide range of units for length, mass, and other quantities, with a nine-row converter for any measurement. ### Is Calculator ft+ suitable for advanced programming? Absolutely. The RPL mode is powered by the newRPL engine and offers an unlimited typed object stack, soft menus, and the ability to store and run programs, making it suitable for complex programming tasks. ### What is the price of Calculator ft+? Calculator ft+ is a paid application, priced at $5.99. This one-time purchase grants access to all its features and capabilities. ### Does Calculator ft+ have ads? No, Calculator ft+ does not contain advertisements. It is a premium application designed to provide an uninterrupted user experience. ## Version history (last 1 release) ### 1.0 — 2026-09-08 No release notes. ## More apps by Marcelo Mejia Cobo - [Scales HD](https://appshunter.io/ios/app/scales-hd/id418843481) - [Telefunken Scores](https://appshunter.io/ios/app/telefunken-scores/id6802945401) All apps by Marcelo Mejia Cobo: https://appshunter.io/developer/365496933 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-12.*