$ dates --diff --business
Math and conversionDate Calculator
Days between dates, deadlines in business days with Brazilian holidays already subtracted, exact age and the year's calendar — no spreadsheet, no counting on your fingers.
- 100% in your browser
- free
- no sign-up
Result
Enter the dates to see the result.
Four calculations nobody can do in their head
- Difference between dates — how many days until the trip, how long ago the contract started, how long the project ran. Broken down into calendar days, business days, weekends and holidays.
- Add or subtract — the due date 45 days from now, the 15-business-day deadline, the 5-year contract anniversary. Accepts calendar days, business days, weeks, months and years.
- Exact age — in years, months and days, with the total days lived and a countdown to the next birthday.
- Holidays — the Brazilian national calendar for any year, with the movable dates computed and holidays told apart from optional days off.
Calendar days or business days? The question that changes everything
Both kinds of deadline exist and are counted differently — swapping one for the other is the mistake that loses court deadlines and blows through SLAs.
Calendar days count everything: weekends, holidays, Christmas. It is the default rule of the Brazilian Civil Code and the most common in consumer deadlines, such as the 7-day right of withdrawal in online purchases.
Business days skip Saturdays, Sundays and holidays. That is the rule for court deadlines since the 2015 Civil Procedure Code (art. 219) and the convention in most service contracts. In this count the starting day does not enter, and if the last day falls on a non-business day the deadline extends to the next business day — the calculator already does that.
National holiday vs. optional day off
This distinction rarely shows up in competing calculators, and it is the one that causes most arguments in an office. A national holiday is what federal law establishes: 1 January, Good Friday, 21 April, 1 May, 7 September, 12 October, 2 November, 15 November, 20 November (national since Law 14,759/2023) and 25 December.
An optional day off is an administrative decision by the federal government for its own agencies — the case of Carnival (Monday and Tuesday), Ash Wednesday and Corpus Christi. They bind nobody in the private sector, even though almost everything stops. The tool separates the two groups and lets you decide whether they enter the count.
Beyond that list there are state and city holidays, which vary by location (city anniversary, patron saint, state historical dates). They are not included here and must be checked against local legislation.
How the movable holidays are computed
Carnival, Good Friday and Corpus Christi shift every year because they depend on Easter, which is the first Sunday after the first full moon following the March equinox. The tool computes Easter Sunday with the anonymous Gregorian algorithm (Meeus/Jones/Butcher) and derives the rest by offset: Good Friday is 2 days before, Carnival Tuesday 47 days before, and Corpus Christi 60 days after. Nothing is hard-coded in a table — which is why any year works, past or future.
Where this calculation meets the others
Dates are usually the first step of a bigger calculation. To close out the month in hours and minutes, use the hours calculator. To turn contract time into payouts, the severance calculator and the vacation calculator start from exactly the hiring and termination dates.
No time zone, no off-by-one
Every calculation runs in UTC, treating each date as a civil date — no time, no zone. That is the safeguard against the most common bug in date calculators in Brazil: a date created at local midnight becomes the previous day once converted, and the result is wrong by exactly one day. Since the whole computation happens in your browser, nothing is sent to any server.
## faq
Frequently asked questions
How do you count the days between two dates?
Enter the start and end dates in the "Difference between dates" tab. The tool shows four numbers: calendar days (the distance between the two dates), business days, how many Saturdays and Sundays fall in the period, and how many holidays. The calendar-day count is exclusive — 1 to 2 January is 1 day — while the other three include both ends, because that is how you count "how many days will I work between X and Y".
Are Carnival and Corpus Christi national holidays in Brazil?
No. Legally they are optional federal days off, not statutory national holidays — the difference is labelled on each date in the "Holidays" tab. In practice most shops, banks and offices close, so the calculator offers the option of subtracting them from business days. For contractual or court deadlines the rule usually counts only the statutory national holidays, which is why the option is off by default.
Which are the Brazilian national holidays?
They are: 1 January (New Year), Good Friday, 21 April (Tiradentes), 1 May (Labour Day), 7 September (Independence), 12 October (Our Lady of Aparecida), 2 November (All Souls), 15 November (Republic Proclamation), 20 November (Black Awareness Day, national since Law 14,759/2023) and 25 December (Christmas). State and city holidays — such as a city's founding anniversary — are not on this list and must be checked locally.
How do you calculate a deadline in business days?
Use the "Add or subtract" tab, choose the "business days" unit and enter the deadline. The count excludes the starting day and always lands on a business day — if the last day falls on a weekend or a holiday, the deadline extends. That is the rule of article 219 of the Brazilian Civil Procedure Code for court deadlines and the convention used in service-level agreements. Always check whether your case runs on business days or calendar days: consumer deadlines, for instance, are usually calendar days.
How is the exact age calculated?
By counting calendar years, months and days, not by dividing the total number of days by 365. Someone born on 31 January completes one month on 28 February, not on 2 or 3 March — months have different lengths and the calculation respects that. The tool also shows the total days lived and how many days are left until the next birthday, useful for tracking contribution time, contract time and warranty periods.
Why does adding one month to 31 January give 28 February?
Because that is the convention used in contracts, due dates and subscriptions: when adding months, the day is preserved whenever it exists in the target month and, when it does not, it falls back to the last day of that month. If the rule were to add 30 days, 31 January would become 2 March and the due date would drift across months. February in a leap year follows the same logic and lands on the 29th.
How do I find out how many business days a month has?
Put the first and last day of the month into the "Difference between dates" tab and read the "Business days" field. An ordinary month in Brazil has between 19 and 23 business days, depending on where the weekends and holidays fall. That number is the basis for the daily rate in payroll and for a team's capacity in planning.
Does my computer time zone affect the result?
No. Every calculation runs in UTC, with the date treated as a civil date — no time, no time zone. This is the safeguard against the classic "off by one day" error for anyone west of Greenwich, which includes all of Brazil: in many calculators a date created at local midnight becomes the previous day once converted, and the result is wrong by exactly one day.
## other tools