Convert between GPS coordinates (WGS-84), the GCJ-02 datum used by Chinese map providers (AMap/Tencent, a.k.a. "Mars coordinates"), and Baidu's BD-09 datum.
Standard public algorithms; GCJ-02 โ WGS-84 uses iterative inverse with ~1 m accuracy. Coordinates outside mainland China are returned unchanged.
Three common percentage calculations in one place.
Bill total, tip %, and number of people โ get per-person amounts instantly.
Original price + discount % โ final price and savings.
Exact age in years, months and days โ plus days until your next birthday.
Body Mass Index with WHO categories: <18.5 underweight, 18.5โ24.9 normal, 25โ29.9 overweight, โฅ30 obese.
Initial deposit + monthly contributions, compounded monthly.
Monthly payment, total interest and payoff for a fixed-rate loan.
Length, weight and temperature conversions.
Days between two dates, or add/subtract days from a date.
Strong random passwords generated locally in your browser โ nothing is sent to any server.
Words, characters, sentences and reading time โ great for essays, posts and tweets.
Turn any URL or text into a QR code, generated locally in your browser.
Beautify or minify JSON.
Mifflin-St Jeor equation for BMR and daily calorie needs (TDEE), plus cutting/bulking targets.
Naegele's rule: estimated due date = first day of last menstrual period + 280 days.
Cryptographically random integers in any range โ great for giveaways and raffles.
Convert text to and from Base64 (UTF-8 safe).
Pick a color and get HEX, RGB and HSL values โ handy for design and front-end work.
Compress JPG/PNG/WebP entirely in your browser โ images never leave your device.
Combine multiple PDF files into one, in order โ processed entirely in your browser.
Extract a page range from a PDF into a new file.
Convert between GPS coordinates (WGS-84), the GCJ-02 datum used by Chinese map providers (AMap/Tencent, a.k.a. "Mars coordinates"), and Baidu's BD-09 datum.
Standard public algorithms; GCJ-02 โ WGS-84 uses iterative inverse with ~1 m accuracy. Coordinates outside mainland China are returned unchanged.
Convert decimal degrees (DD) to degrees-minutes-seconds (DMS) and back, e.g. 116.397428ยฐ = 116ยฐ23โฒ50.7โณ E.
Upload or paste a GeoJSON file and batch-convert every coordinate (Point / LineString / Polygon / FeatureCollection) between WGS-84 / GCJ-02 / BD-09 โ processed entirely in your browser.
Convert latitude/longitude (WGS-84) to and from UTM grid coordinates (Easting / Northing) using standard Transverse Mercator formulas (kโ = 0.9996). Zone is auto-detected from longitude, or set it manually.