utilduck is a flock of everyday tools. The name joins utility and duck — like the rubber duck on a programmer's desk, it sits quietly beside you while the small calculations of daily life get done: percentages, dates, units, passwords, conversions.
Everything runs entirely in your browser. Nothing you type is sent to a server: your numbers, dates and text stay on your device, and results appear as you type. There is no account, no paywall and no clutter.
We believe a good tool should explain itself. Every page shows the formula and the reasoning behind the result, so you can check the math yourself instead of trusting a black box.
The flock keeps growing: calculators, converters, health, dates, office, developer and study tools — in English, Korean, Japanese, Chinese, German, French, Spanish, Vietnamese and Indonesian.