Date Calculator

By default, this calculator uses exclusive counting — the start date is not included. January 1 to January 2 = 1 day. This is the international standard used by Excel's DATEDIF() function, JavaScript's Date object, and most programming languages. It's also how the IRS counts deadlines: "within 60 days" of January 1 means the deadline is March 2, not March 1. For inclusive counting (both dates counted), add 1 to the result — January 1 to January 10 becomes 10 days instead of 9. Inclusive counting is used in some lease agreements, medical quarantine periods, and certain state statutes of limitations. The practical impact can be significant: a "30-day notice" under exclusive counting ends on a different day than under inclusive counting, which could mean the difference between a valid and invalid legal notice. See our detailed FAQ on inclusive vs exclusive counting below for legal examples.

Business days (working days) are Monday through Friday, excluding weekends. This calculator counts weekdays between your two dates automatically. Federal holidays are displayed in the reference table but are not automatically excluded from the business day count because holiday observance varies: federal employees get all 11 federal holidays off, but private employers are not legally required to observe any of them (no federal law mandates paid holidays). A typical year has approximately 252 business days (365 − 104 weekend days − ~9 weekday-falling holidays). This figure drives payroll math: a $60,000 salary equals approximately $238/business day or $29.76/hour at 8 hours/day. For shipping estimates, "5–7 business days" means 7–9 calendar days when weekends are added. Use the Salary Calculator to convert between annual, hourly, and per-paycheck amounts using this 252-day standard.

Yes — leap years are automatically handled in all calculations. The Gregorian calendar rule: a year is a leap year if divisible by 4, except century years (divisible by 100) — unless also divisible by 400. So 2024, 2028, and 2032 are leap years; 2100 and 2200 will not be; but 2000 and 2400 are. This produces an average year length of 365.2425 days. The practical impact: January 1 to December 31 spans 365 days in a regular year and 366 in a leap year. Date ranges crossing February 28/29 are affected — "60 days from January 1" lands on March 2 in a regular year but March 1 in a leap year. For financial planning, leap years add one extra business day approximately 70% of the time (when Feb 29 falls on a weekday). The next leap years are 2028, 2032, and 2036. Check your exact age accounting for all leap years with the Age Calculator.

The United States observes 11 federal holidays in 2026, established by 5 U.S.C. §6103: New Year's Day (Jan 1), Martin Luther King Jr. Day (3rd Mon in Jan), Presidents' Day (3rd Mon in Feb), Memorial Day (last Mon in May), Juneteenth (Jun 19), Independence Day (Jul 4), Labor Day (1st Mon in Sep), Columbus Day (2nd Mon in Oct), Veterans Day (Nov 11), Thanksgiving (4th Thu in Nov), and Christmas Day (Dec 25). When a holiday falls on Saturday, it's observed the preceding Friday; on Sunday, the following Monday — this is the Saturday/Sunday observance rule under Executive Order 11582. Juneteenth was added as the newest federal holiday in 2021 (P.L. 117-17). Private employers are not required to provide paid holidays — approximately 79% of private workers receive paid holidays (BLS), with an average of 8 days. See the full date table with 2026 observance dates in the reference section above.

Yes — use the Add/Subtract Days mode. Enter a number of calendar days to add, then check the business day count in the results to see how many working days that spans. For a quick conversion: multiply business days by 1.4 to estimate calendar days (e.g., 10 business days ≈ 14 calendar days, 20 business days ≈ 28 calendar days). This 1.4x multiplier accounts for weekends (5 work days per 7 calendar days = 7/5 = 1.4) but not holidays, so during holiday-heavy periods (November–January has 4 federal holidays) the actual calendar days will be slightly higher. Common business-day deadlines: IRS 21 business days for e-filed refund processing, bank 3–5 business days for ACH transfers, passport 6–8 weeks (30–40 business days) for routine processing. Track your next quarterly estimated tax deadline in business days.

Enter your start and end dates — the calculator automatically displays both total calendar days and business days (weekdays) side by side. The difference between the two numbers reveals how many weekend days fall in your range. For example, a 30-calendar-day span starting on a Monday contains 22 weekdays and 8 weekend days. This dual display is useful for: project management (estimating work effort vs. elapsed time), shipping (converting "5–7 business days" to expected delivery date), payroll (calculating daily rate — a biweekly $2,500 paycheck covers 10 business days = $250/day), and legal deadlines (some contracts specify "business days" while others use "calendar days"). The weekday count excludes Saturday and Sunday but includes federal holidays that fall on weekdays. See how business days affect your pay with the Salary Calculator.

The IRS filing deadline shifts to the next business day when April 15 falls on a weekend or holiday. If April 15 is Saturday, the deadline moves to Monday, April 17. If April 15 is Sunday, it moves to Monday, April 16. A unique complication: Emancipation Day (April 16) is a legal holiday in Washington, D.C., and the IRS recognizes D.C. holidays for nationwide filing deadlines. If April 15 falls on Friday and April 16 (Emancipation Day) falls on Saturday, D.C. observes it on Friday April 15 — pushing the deadline to Monday April 18. This has happened multiple times (2011, 2016). Use this calculator to count exact days remaining until your filing deadline, then estimate your tax liability with the Income Tax Calculator. Quarterly estimated tax deadlines (April 15, June 15, September 15, January 15) follow the same weekend/holiday shift rule.

The standard work year varies depending on what you count: 2,080 hours (52 weeks × 40 hours) is the gross figure used by the Department of Labor and most salary calculators. Subtracting 9 weekday federal holidays gives approximately 2,016 hours (252 business days × 8 hours). With the BLS-reported average of 15 days paid time off, actual work hours drop to approximately 1,896 hours (237 days × 8 hours). For overtime-eligible workers, anything above 40 hours/week (or 8 hours/day in some states like California) triggers 1.5x pay. These figures matter for salary conversion: $60,000/year ÷ 2,080 hours = $28.85/hour gross, but ÷ 1,896 actual hours = $31.65/hour effective. The Salary Calculator uses the 2,080-hour standard for annual-to-hourly conversion, matching IRS and DOL methodology.

The ISO 8601 week numbering system assigns every day of the year to a numbered week (W01–W52 or W53). Week 1 is defined as the week containing the first Thursday of January, which means January 1 can fall in Week 52 or 53 of the previous year. For example, January 1, 2026 (Thursday) is in W01 of 2026, but January 1, 2028 (Saturday) will be in W52 of 2027. This system is standard in international business, manufacturing (production schedules reference "W15"), European payroll systems, and project management (Gantt charts use ISO weeks). The US traditionally uses Sunday-start weeks, while ISO weeks start on Monday. This difference causes a 1-day offset in weekly reports and can create confusion in multinational teams. Most spreadsheet software supports both: Excel's WEEKNUM() uses US weeks, while ISOWEEKNUM() uses ISO weeks.

The distinction between inclusive and exclusive counting has real legal and financial consequences. Exclusive counting (this calculator's default): the start date is not counted. January 1 to January 10 = 9 days. This is the standard for most programming languages, IRS deadlines, and financial settlement periods. Inclusive counting: both start and end dates are counted. January 1 to January 10 = 10 days. This is used in some lease agreements (a "30-day notice" starting January 1 includes January 1 as day 1, making the last day January 30), statute of limitations calculations in many states, and medical quarantine periods (CDC counts the exposure date as day 0). Federal Rule of Civil Procedure 6(a) specifies: "exclude the day of the event that triggers the period." Missing a legal deadline by one day due to counting method confusion can result in case dismissal, penalty fees, or forfeited rights. Always confirm which method applies to your specific situation.

Since May 28, 2024, US securities settle on T+1 — one business day after the trade date (SEC Rule 15c6-1(a)). This replaced the previous T+2 system, reducing settlement risk by approximately $1.6 billion per day according to the DTCC. Practical examples: a stock sold on Monday settles Tuesday. Sold on Friday settles the following Monday. Sold on Wednesday before Thanksgiving settles Friday (Thursday is a holiday). This matters for: tax-loss harvesting — the trade date (not settlement date) determines the tax year, so selling on December 31 counts for that year's taxes even though settlement occurs January 2. Dividend eligibility — you must own the stock by the record date, which requires purchasing at least 1 business day before (T+1 settlement). Wire transfers — proceeds from a stock sale are available in your brokerage account on the settlement date, not the trade date. Use this calculator to count business days for any T+1 scenario.