Working days: classify each date once
The main business-days calculator starts with the selected range and applies its start/end switches. Each included date is then classified in this order: outside the selected workweek; holiday or additional day off on a working day; otherwise business day. The three counts sum to the total included dates.
Business days = included dates − scheduled days off − holidays on scheduled working days. A date appears in one category. Repeating a holiday does not remove another day, and a holiday on a scheduled day off is not subtracted twice. The default workweek is Monday to Friday; the main tool and annual guides also support Saturday work and custom weekdays.
Check the rule with a short interval
July 17–20, 2026, with both endpoints and no holidays, contains Friday, Saturday, Sunday and Monday. A Monday–Friday workweek gives 4 total dates − 2 days off = 2 business days. Excluding the starting Friday leaves 1 business day. Working Saturday gives 3 business days when both endpoints are included.
When the same date is selected twice, it counts once only if both endpoint switches include it. An excluded endpoint remains visible in the calendar with the reason for exclusion. Ranges longer than 3,660 days between endpoints are rejected rather than truncated.
Holiday source and coverage
Holiday-aware tools load country/year records from Nager.Date. The baseline uses records marked country-wide by the source. Selecting a region in the main tool or an annual guide adds matching subdivision records. Public and bank types are included; records marked optional or observance are excluded. The source scope is not proof of entitlement for every employer or activity.
Records are merged by date. Observed dates are used as returned: the calculator does not automatically move every Saturday holiday to Friday or Monday. Municipal holidays, company leave and incomplete regional coverage may require additional dates. The main counter and annual guides provide that field; the simpler deadline, delivery, invoice and date forms use only the country-wide baseline.
For Brazil, the baseline excludes Carnival, Corpus Christi and Easter Sunday; it includes the fixed national dates and Good Friday in the federal reference calendar. Local religious holidays and employer practice may differ. Canada’s country-wide source baseline is not a federal employment entitlement calendar. The UK guide starts with England, with other nations available in its region selector.
If a request fails or its response is invalid, the requested result is hidden and an error is displayed. Successful data is cached for the page session; failed requests can be retried. Choosing no holidays is an explicit alternative, never an automatic fallback. Read the provider’s data coverage documentation and the relevant official calendar when checking a particular holiday.
Annual guides and reference tables
General guides begin without holidays: a Monday–Friday schedule has 261 days in 2026, 261 in 2027 and 260 in leap year 2028. These are unadjusted weekday totals, not universal working-day counts. A specific country, region, schedule or additional day off can change them.
Monthly counts are calculated date by date, and each quarter adds its three monthly working-day counts. The quarterly sum therefore matches the annual total. Static tables use source records checked on October 17, 2026. Interactive calculations request live records and can reflect subsequent source corrections; the static verification date is not a claim of continuous real-time review.
For the default US source baseline in 2026, 365 dates − 104 weekend dates − 11 weekday holiday dates gives 250 business days. Compare observed federal dates with the OPM calendar and confirm the calendar relevant to the employer.
Calendar dates, endpoints and month ends
The date calculator adds or subtracts calendar units. A week is seven calendar days. Months and years preserve the day number where possible and clamp to the last valid date otherwise: January 31, 2026 + one month becomes February 28, while +30 calendar days becomes March 2.
The days-between tool normally measures the gap from the earlier date to the later date. Its weekday/weekend split uses the earlier date up to, but not including, the later date. The inclusive switch adds that last date. It orders reversed inputs and reports a positive interval. Holidays are not removed from its weekday tile.
Its years/months/days description refers to the original interval even when the inclusive switch adds a date to the total. Calendar differences use whole dates rather than assuming each month has a fixed duration. Equivalent hours and minutes use 24 hours per calendar day; a date-only input cannot establish exact elapsed clock time across a daylight-saving transition.
Deadlines, deliveries and invoice terms
Adding business days excludes the starting date: it is day zero. The tool moves forward or backward one date at a time, skipping Saturday, Sunday and the selected country-wide holidays. Holiday data is loaded for every year actually crossed; there is no fixed two-year window.
Friday July 17, 2026 + one business day without holidays is Monday July 20. With the US baseline, July 2 + one business day is July 6 because July 3 is an observed holiday. Subtracting one day from an ordinary business day uses the same rules in reverse.
Delivery estimates add handling and minimum/maximum transit to produce two dates. They do not consult tracking, cutoff times, customs or live carrier services. Use zero handling when dispatch has already occurred. Invoices use either calendar days or business days as selected; July 17, 2026 +30 calendar days is Sunday August 16 and is not automatically shifted to Monday.
These numerical conventions do not determine contractual, judicial or banking deadline rules. The selected starting event, calendar and any adjustment must match the process being modeled.
Age, months and date countdowns
For years/months/days, the tools find the largest whole number of calendar months from the starting date that does not pass the end date, clamp the target day for shorter months, then count remaining calendar days. Every 12 months forms a year. January 31 to March 1, 2026 is therefore 1 month and 1 day, not a negative day remainder.
Age is measured at the chosen reference date. The age breakdown can complete a clamped month at February’s end, while the separate birthday countdown uses March 1 for February 29 birthdays in non-leap years. These are display conventions, not a decision about age eligibility.
Days-until uses the device’s local date: tomorrow is one day away and today is zero. Past targets show days since. Hours shown in these date-only tools are calendar-day equivalents, not an exact timer from a known time of birth or until an event time.
ISO week number and week-year
Weeks start on Monday. Week 1 contains January 4, equivalently the first Thursday of the year. The ISO week-year can differ from the calendar year near New Year: January 1, 2021 is week 53 of 2020; January 4 begins week 1 of 2021.
The day-of-year and quarter figures describe calendar positions without subtracting holidays. Compare week numbers only after confirming the same first-week and week-start rules in the other calendar. For an unambiguous date in an example or support report, use YYYY-MM-DD.
Time-zone conversion and scheduling bands
The input date and time represent the device’s local time zone, shown by the form. Destinations are formatted for the same instant using each city’s IANA zone through the browser’s Intl.DateTimeFormat support. The selected date determines the offset, including the browser’s daylight-saving rules.
For example, January 15, 2026 at 15:00 UTC is 10:00 in New York, 15:00 in London and 00:00 on January 16 in Tokyo. That example starts from a stated UTC instant, not an arbitrary device-local 15:00.
The highlighted 09:00–18:00 band is a generic daytime window, without personal availability or holidays. Shared links retain the date, time fields and cities; the receiving device still interprets the base fields in its local zone. Confirm the origin zone when sharing, and treat repeated or missing local times around clock changes carefully.
Pricing, margin and marketplace-fee formulas
In the margin tool, C = entered unit costs, m = desired margin, t = tax rate and f = platform rate, using decimal rates. Price = C / (1 − m − t − f), with a positive denominator. Profit deducts those costs and percentage amounts; margin = profit / price. A cost of 60 and target margin of 25%, without other deductions, produces a price of 80 and profit of 20.
The tool’s displayed markup indicator uses profit after entered percentage deductions divided by C. With no such deductions it matches the usual cost-based markup. Otherwise it differs from gross price uplift, (price − C) / C. The visual margin bands are not industry benchmarks.
For marketplace fees, fees = sale × commission + fixed marketplace fee + sale × payment rate + fixed payment fee. Both percentages use the same entered sale amount. Payout subtracts fees; profit also subtracts entered costs. On a hypothetical sale of 100 with 10% +1 marketplace fees and 3% +0.50 payment fees, fees are 14.50 and payout is 85.50.
Rates are inputs, not live platform tariffs. Presets are editable examples. The currency choice does not convert values. Taxes, refunds, conversion costs and overhead are absent unless represented in the inputs; the tax field is a simplified percentage, not a complete fiscal model.
Illustrative cheque fields
The Portuguese cheque tool formats entered fields and writes a BRL amount in words, including centavos. The preview is illustrative and does not issue a cheque or access a bank account. It does not validate a signature, balance, identity, bank acceptance or a compensation deadline.
Check the written amount against the displayed numerical amount before copying. Any banking conditions for a real cheque must be confirmed with the bank. The tool’s purpose is field and spelling review.
Reproduce a result or report a difference
Record the page, input dates or amounts, country/region, workweek, endpoint switches and extra days. For time-zone conversions, also record the device’s origin zone. Those settings are necessary to reproduce the same question.
Use Contact & Feedback to report a discrepancy with a small example and the expected result. Published explanations should describe the current calculation; a verified change to a rule or source should be followed by updated examples and reference tables. See About BusinessDaysTool for the project’s scope.