Convert
Any base from 2 to 36. Two's complement, one's complement and sign-magnitude at 8 to 64 bits. IEEE 754 half, single, double and bfloat16. Fixed point in Q notation, BCD, Gray, Excess-3 and UTF-8 text.
Education · Android · iOS
BaseWhiz
A number-base calculator for CS students. Converts between bases, two's complement, IEEE 754 floats, fixed point and text, and shows every step of the working, the way an exam asks for it.
Screens
What it does
Steps
Shows the working: repeated divisions, place values, and the sign, exponent and mantissa of a float. Says when an answer is exact and when it was rounded.
Calculate
Exact big-number maths. Bitwise ops in an 8 to 64-bit word with carry, overflow, zero and negative flags.
Bits
A bitboard of up to 64 bits to flip, shift, rotate, invert and byte-swap. Reads its bytes in both orders.
Practice
Rounds of ten questions with steps and a streak, plus a new question of the day.
Copy as code
Hold Copy for a C or Python literal, the word's bytes in big- or little-endian order, or the UTF-8 bytes of text.
Widgets
Home-screen widgets for the question of the day, with its streak, and the last conversion in four bases. Launcher shortcuts on Android.
From anywhere
Select a number in another app and choose Convert in BaseWhiz. On iPhone, Siri and Shortcuts run Convert number.
Private
No ads, no account, no internet permission. A searchable, pinnable history stays on the device.
How it's built
| Layer | Tech | Notes |
|---|---|---|
| Shared | Kotlin 2.4 Multiplatform, Room KMP with bundled SQLite | Conversion engine, ViewModels, history, question of the day and widget data |
| Android | Jetpack Compose, Material 3 | Navigation Compose. Two panes on tablets, hardware keyboard shortcuts |
| Android extras | Jetpack Glance, PROCESS_TEXT, launcher shortcuts | Two home-screen widgets; Convert in BaseWhiz on selected text |
| iOS | SwiftUI + Observation, SKIE interop | iPhone and iPad. iOS strings generated from the Android XML |
| iOS extras | WidgetKit, App Intents, action extension | Two widgets, Siri and Shortcuts, Convert in BaseWhiz on selected text |
| iOS storage | App Group | App, widgets and action extension share history and settings |
| Engine | Pure-Kotlin PortableBigInteger | Used on iOS; fuzz-tested against java.math |
| Backend | None | Fully offline |
Origin
A rewrite
BaseWhiz started as a rewrite of an earlier Flutter app, Advanced CS Calculator.