GoodTools

**GoodTools — 20 handy tools in one tiny, offline app.** No sign-up. No account. No ads. No network access. Just open it and get the answer you need — a calculator, a stopwatch, a coin toss, a spinning globe, and much more. **Everything works offline.** Every tool is built in and every result is computed on your device. GoodTools never connects to the internet, never collects your data, and the only permission it asks for is vibration. Your notes and stopwatch time stay on your phone. **ALL 20 TOOLS** **Everyday** • Calculator — fast four-function math with a 12-digit display • Stopwatch — start, pause, resume, lap and reset, with precise MM:SS.CC timing and a lap list • Countdown Timer — set hours, minutes and seconds with wheels, then watch a big full-screen countdown • Note — a full-screen notepad that saves automatically as you type, so nothing is ever lost • Toss Coin — tap anywhere to flip a coin and settle any decision, with a satisfying buzz on landing **Math & Numbers** • Factorial — exact factorials of any number up to 1000, shown in full with no scientific notation • Factorizer — break any number up to 100,000,000 into its prime factors, like 2^3 × 3^2 • Prime Checker — check a number of up to 20 digits, then scroll on for the next 30 numbers with instant prime/not-prime marks • Random Number — one tap for a fresh random 6-digit number • Pi 10000 — the first 10,000 digits of π in a clean monospaced view you can scroll, select and copy • Constants — 14 essential physical and mathematical constants, including π, e, the speed of light, Planck's constant, Avogadro's number and the golden ratio **Converters** • Temperature Converter — slide smoothly between Celsius and Fahrenheit in 0.1° steps from -30 °C to 120 °C • Angle Converter — drag the arm to any angle from 0° to 359° and read it instantly in degrees, radians and multiples of π **Clocks & Time** • Time — a bold, full-screen clock that fills the display and ticks every second • Year Progress — see exactly how much of the year has passed, down to six decimal places, on a live progress ring **Play & Explore** • Cube — a glowing 3D cube you can spin freely with your finger • Globe — a real 3D Earth with coastlines, rendered in OpenGL and ready to spin • Emoji — 336 emoji in a tidy grid; tap any one to copy it straight to your clipboard • Vibrate — press and hold anywhere for a steady vibration, up to 10 seconds **WHY YOU'LL LIKE IT** • Truly offline — works in the subway, on a plane, anywhere • Instant — every tool opens and responds immediately • Clean and simple — a tidy grid of icons, no clutter and no learning curve • Lightweight — a small download that stays out of your way • Handy extras — long-press-free copying, one-tap sharing, and a direct link to rate the app • Made for everyone — English and Chinese, light and dark mode, and support for both portrait and landscape **WHO IT'S FOR** Students checking homework, engineers and makers doing quick calculations, teachers in the classroom, travelers without a signal, and anyone who wants a dependable set of small tools without ads or distractions. **PRIVACY FIRST** GoodTools has no internet permission, so your information literally cannot leave your device. There are no trackers and no analytics. The only permission requested is VIBRATE, used solely for the coin toss, emoji copy and vibrate tools. **ABOUT** GoodTools is a small, carefully made app by an independent developer. Tools are built one at a time and polished until they feel right. If you have an idea for the next tool, send your feedback from the side menu — it is genuinely read. Download GoodTools today, and keep 20 useful tools in your pocket.