Beyota is the calculator you'll actually want to look at. 56 built-in themes, and none of them are just a recolour. Themes change the shape of the keys too — raised tiles, borderless circles, hard-ruled grids, deep soft pillows, embossed keys, translucent glass. 17 are built on real photographs: an ocean afternoon, an anime night sky, Earth from space, a golden desert at sunset. 20 are dark. Others sweep gradients corner to corner, or glow in neon outline. Browse them in a gallery where every card is a working miniature of the calculator in that theme, so you see exactly what you're getting. Search by name, sort by popularity or A-Z, filter by category. Click one and the entire app re-skins instantly — no restart, no Apply button — and it's still there the next time you open it. The theme goes everywhere, not just the keypad: the display, the menu, the settings screen, the unit converter, and the date calculator right down to its pop-up calendar. Underneath the style, it's a serious calculator. Standard, Scientific and Programmer modes, each with its own hand-built portrait and landscape keypad that swaps automatically when you resize. Standard and Scientific share one live calculation, so switching between them mid-sum keeps your value, memory and history intact. Arithmetic runs in exact decimal, so money-style sums stay precise. Scientific adds squares and cubes, roots, factorial, reciprocal, exponentials and logs, the full trig and hyperbolic set with inverses behind a 2nd key, a degrees/radians toggle, and dedicated π, e and random keys. Programmer shows HEX, DEC, OCT and BIN all at once, every row live on every keystroke — tap one to type in that base. Four word sizes (QWORD, DWORD, WORD, BYTE) with true register-width masking, bitwise AND, OR, XOR and NOT, left and right shifts, and MOD. Digit keys grey themselves out to match the active base. A unit converter covers 38 units across length, weight, temperature, volume, area and speed, with its own keypad. A date calculator finds the difference between two dates — as years, months and days, plus the total in days — or adds and subtracts years, months and days from a date, and tells you which weekday you land on. Every date field opens a real pop-up calendar you can drill from month to year to decade. Results update as you type; there's no equals button to hunt for. Everything else you'd want: a history flyout that remembers your last 50 calculations and puts any of them back in the display with a click, full keyboard entry, a keep-on-top pin so the calculator floats above your work, a one-click portrait/landscape flip, and a frameless themed window with its own rounded chrome. Beyota speaks 9 languages and switches between them instantly. It opens in your Windows display language the first time you run it. And it is completely offline. There is no networking code in the app at all — no accounts, no ads, no telemetry, no analytics, no crash reporting. Your settings and history are two small files on your own PC, and turning history off deletes its file outright.