Phonio CLONE-40B is a free, offline desk calculator and installable PWA with a 14-digit display. This accountant-style calculator does tax calculation, currency conversion with exchange rates, grand total (GT), independent memory, markup & profit margin, percentage and square root — fully offline, with keyboard shortcuts.
- F · CUT · 5/4 — Rounding selector: F = floating point, CUT = truncate (round down), 5/4 = round half up.
- 4 3 2 1 0 A — Decimal-place selector. A = Add mode (auto 2 decimals). Ignored when F is selected.
- TAX+ / TAX− — Tax calculation: add or remove sales tax / VAT. Press again to show the tax amount only.
- M/EX (MODE) — Toggle currency conversion mode; the EXCH indicator turns on.
- Currency conversion — In EXCH mode the C1–C4 keys (M+ M− MR MC) select currencies; C1 is the home currency. Set a rate: % (SET) → currency key → rate → % (SET). Convert: type an amount → its currency key → the target currency key.
- % — Percent and profit margin / markup. √ square root, ▶ backspace, +/− sign change.
- GT — Grand total: accumulates every = result; press twice to clear.
- MC MR M− M+ — Independent memory (when EXCH is off). C clears the current entry, AC clears everything.
- Keyboard shortcuts — digits, + − * /, Enter (=), Backspace (▶), Esc (AC), %, m (M+).