Working Days Calculator

WHAT IT DOES

Working Days Calculator gives you precise business day counts between any two dates. Enter a start and end date, and the panel instantly shows the number of working days, calendar days, weekend days, holidays excluded, and working weeks. You can customize which days of the week count as working days — perfect for regions where the work week differs from Monday-Friday. Add custom holidays to exclude specific dates from the count. This tool is essential for project planning, contract timelines, delivery estimates, payroll calculations, and any scenario where you need accurate business day counts.

WHERE IT RUNS

This script runs on every website you visit. Whether you are planning projects on task management platforms, calculating delivery dates on e-commerce sites, tracking employee leave on HR systems, or estimating timelines on construction management tools, the panel is always available. It works alongside your existing tools without interfering with your workflow.

HOW TO USE

Select the start and end dates using the date pickers. The results update automatically. Customize your working week by checking or unchecking individual days of the week. Add holidays by selecting a date and clicking "Add" — holidays appear as tags that can be removed with a single click. The results show the total working days, calendar days, weekend days, holidays excluded, and working weeks. Click any history entry to reload previous date pairs. Use the "Copy Result" button to copy the working days count and calendar days to your clipboard.

THE ACCURATE WORKING DAYS MECHANISM

Working Days Calculator iterates through every day in the date range, checking each date against three criteria: is it a working day of the week (based on your selection), is it a holiday (based on your holiday list), and is it within the date range. This per-day iteration ensures 100% accuracy — no off-by-one errors or formula approximations that can occur with mathematical calculations. The algorithm handles date ranges of any length up to the JavaScript Date limit, and the holiday list is stored persistently in your browser. Weekend detection automatically accounts for Saturday and Sunday, while holiday comparison uses exact date matching. The working weeks calculation divides the total working days by 5 and rounds up, giving you a practical estimate for project planning.

THE PANEL

The panel is fully draggable and remembers its position per site. It minimizes to a compact floating bubble when collapsed. All settings — working day preferences, holiday list, and calculation history — persist across browser sessions using GM_setValue storage. Press the Escape key to close the panel. The panel automatically focuses the start date input field for quick keyboard entry.

PLEASE NOTE

This script requires the free BotGentz extension to run. Holiday dates are stored locally and are not shared with any external service. The working days count is accurate for the Gregorian calendar from 1900 onward. Always verify critical business dates with your official systems. Websites change their structure and behavior over time; if any functionality stops working, the script may need an update. No user data is sent anywhere — all settings, holidays, and calculation history are stored locally in your browser. The script never reads or modifies password, hidden, or file input fields.