What the project is for
BusinessDaysTool brings together calculators for working days, date intervals, deadlines, time zones and basic pricing scenarios. It is designed for people planning a project, checking an invoice interval, estimating a delivery window or comparing the costs entered for a sale.
The project is identified publicly as BusinessDaysTool. Its focus is on tools whose inputs, counting rules and limitations can be checked. Questions about the project can be sent through the contact page.
Choose the tool for the question
There is a difference between counting an existing interval and finding a future date. The business-days calculator counts a selected period with workweek and holiday options. The deadline calculator moves forward or backward by a stated number of working days.
The invoice calculator makes calendar-day and business-day terms explicit. The time-zone converter compares local displays of the same moment. Pricing tools work from entered amounts and rates; they do not read seller accounts or fetch live marketplace tariffs.
An answer with its assumptions
A useful number needs a counting rule. On the main working-day tool you can inspect individual dates, change the workweek and add days off. The annual guides distinguish an unadjusted weekday baseline from a selected holiday calendar, and show monthly and quarterly totals from the same calculation.
The calculation methodology explains endpoint handling, month-end adjustments, holiday coverage, formula definitions and examples. Each tool also describes its own limits so you can decide whether it matches the task.
How this version was checked
The calendar changes reviewed on October 17, 2026 were checked against stored holiday source records and automated regression tests. Those checks cover duplicate holidays, regional filtering, work schedules, date endpoints, leap years, API failures and delayed responses. Interface checks cover English and Portuguese versions of the calendar tools.
Source snapshots and live data serve different purposes: a snapshot makes a published reference table reproducible; a live request can reflect later source changes. A difference should be investigated and explained, rather than hidden by replacing a failed holiday request with an empty list.
Access and privacy
The tools can be used without an account or payment. Calculations run in the browser. Holiday-aware tools request country and year data from an external source; contact messages use a form service. The site also includes analytics and advertising integrations. Read the Privacy Policy for the services and data practices involved.
Advertising, when displayed, does not change the counting rules or the numbers entered in a calculator. A date or price result is not a carrier guarantee, a legal determination or a complete accounting assessment.
Help make a result easier to verify
If a result seems wrong, use Contact & Feedback. Include the tool, input values, country or region, counting mode and expected answer. For date tools, write the dates in YYYY-MM-DD format so that day and month are unambiguous.
Please use an example that reproduces the issue instead of sending account credentials, a cheque image or an entire customer invoice. The same form can be used for suggestions and questions about the explanations.