About ZenUtility
A small independent collection of practical tools for dates, time and everyday calculations.
Small tools. Less friction.
ZenUtility is an independently operated utility website built around a simple idea: an everyday calculation should be easy to finish and easy to understand. You can use the tools without creating an account or installing an app.
What you will find here
The collection includes date and time tools, everyday calculators, text utilities, developer tools, calendars and focus timers. Each tool explains its method, gives an example and makes the assumptions visible. Browse by category or search for the task you need.
How we maintain the tools
Our calculation checks cover date boundaries, leap years, overnight shifts, standard Roman notation and common conversion errors. Automated tests cannot establish that every answer is suitable for every purpose. Tell us about a problem with the tool URL, inputs and the result you expected.
An independent project
ZenUtility is maintained by its site owner. Questions, corrections and business inquiries can be sent to info@zenutility.com. If you spot an error or have an idea for a useful tool, we would like to hear from you.
Data credits
Holiday calendars are powered by Calendarific (https://calendarific.com/). Prayer calculations use AlAdhan (https://aladhan.com/). City coordinates and time zone references use GeoNames (https://www.geonames.org/) under Creative Commons Attribution 4.0 (https://creativecommons.org/licenses/by/4.0/); ZenUtility maintains local aliases and featured-city selections. Time zone rules are derived from IANA via Moment Timezone, and sun/moon estimates use SunCalc. Third-party libraries retain their original licenses.
Supporting the site
The tools are free to use. Advertising may support the site in the future. The site currently runs without advertising scripts. Advertising will need to remain separate from tool controls and cannot buy a different calculation result.