A collection of free online utilities — health calculators, financial tools, historical weather and air quality lookups, and network calculators. No account or download needed. Just open and use.
Enter your height and weight in metric (cm / kg) or imperial (ft·in / lb) units to instantly get your BMI score, category (Underweight / Normal / Overweight / Obese), and a visual gauge. Ideal weight range for your height is also shown.
Enter principal, annual interest rate, years, compounding frequency (daily / monthly / quarterly / yearly), and optional monthly contributions to see how your investment grows. Includes a year-by-year breakdown table and Rule of 72 estimate.
Pick any date from 1940 onwards and a city worldwide to retrieve hourly temperature, precipitation, humidity, wind speed, and weather condition. Useful for insurance claims, travel planning, research, or satisfying curiosity about a memorable day.
Look up historical hourly PM2.5, PM10, nitrogen dioxide (NO₂), ozone (O₃), and European AQI for any city in the world. Data is available from July 2022 onwards. Useful for health documentation, environmental research, and travel prep.
Enter an IPv4 address and CIDR notation (/24, /16, etc.) to instantly calculate network address, broadcast address, usable host range, subnet mask, and wildcard mask. Essential for network engineers, IT admins, and security students.
Yes, everything is free with no sign-up required. Server costs are covered by advertising.
From Open-Meteo.com's public APIs (CC BY 4.0). Weather coverage starts from 1940; air quality from July 2022. Worldwide city support.
IPv4 only at the moment. It handles the full 0.0.0.0–255.255.255.255 address space with /0–/32 CIDR notation.