--- title: "Date Calculator: Add or Subtract Days From a Date" description: "Free date calculator. Add or subtract days, weeks, months, years or business days from any date, and count the days between two dates. Business days skip US federal holidays." canonical_url: "https://calendarbest.com/tools/date-calculator" locale: en meta: "og:description": "Free date calculator. Add or subtract days, weeks, months, years or business days from any date, and count the days between two dates. Business days skip US federal holidays." "og:image": "https://calendarbest.com/og-image.png" "og:title": "Date Calculator: Add or Subtract Days From a Date | CalendarBest" "twitter:description": "Free date calculator. Add or subtract days, weeks, months, years or business days from any date, and count the days between two dates. Business days skip US federal holidays." "twitter:image": "https://calendarbest.com/og-image.png" "twitter:title": "Date Calculator: Add or Subtract Days From a Date | CalendarBest" --- > Index of every page on this site: [llms.txt](https://calendarbest.com/llms.txt) ## **Add or subtract from a date** Choose a start date and a whole number to add or subtract. ## **Days between two dates** Choose a start and end date to count the days between them. ## **How the date calculator works** Days and weeks are added one calendar day at a time, so the result is the same whatever your time zone and however the clocks change for daylight saving. Months and years keep the day of the month where they can; when the target month is shorter, the result is that month's last day. Business days skip Saturdays, Sundays and US federal holidays on the day they are observed. That is the usual way to count deadlines such as "10 business days" for a delivery or a reply. Check the full [holiday lists](https://calendarbest.com/holidays) if your office closes on other days too. ## **Worked examples** - [**Jan 1, 2027 + 90 days = Thursday, April 1, 2027**](https://calendarbest.com/tools/date-calculator?date=2027-01-01&op=add&n=90&unit=days)A 90-day deadline from New Year - [**Jan 31, 2027 + 1 months = Sunday, February 28, 2027**](https://calendarbest.com/tools/date-calculator?date=2027-01-31&op=add&n=1&unit=months)One month after 31 January lands on the last day of February - [**Dec 24, 2026 + 10 business days = Monday, January 11, 2027**](https://calendarbest.com/tools/date-calculator?date=2026-12-24&op=add&n=10&unit=businessDays)Ten business days, skipping Christmas and New Year - [**Mar 15, 2027 − 6 weeks = Monday, February 1, 2027**](https://calendarbest.com/tools/date-calculator?date=2027-03-15&op=sub&n=6&unit=weeks)Six weeks before a date - [**Feb 29, 2028 + 1 years = Wednesday, February 28, 2029**](https://calendarbest.com/tools/date-calculator?date=2028-02-29&op=add&n=1&unit=years)One year after a leap day ## **Date Calculator FAQ** ### **How do I add days to a date?** Enter the start date, choose Add, type the number of days and leave the unit on days. The calculator moves forward one calendar day at a time, so 90 days after January 1, 2027 is April 1, 2027. To go back in time, choose Subtract. ### **What happens when I add a month to January 31?** Months have different lengths, so the result moves to the last day of the shorter month: January 31 plus one month is February 28 (or February 29 in a leap year). Adding a year to February 29 gives February 28. ### **What counts as a business day?** Monday to Friday, excluding US federal holidays on their observed dates. If you start on a weekend or holiday, adding one business day gives the next working day. ### **How many weeks are in a year?** A year has 52 weeks plus one day, or plus two days in a leap year. In the ISO week system some years, such as 2026, have 53 numbered weeks. ### **Can I calculate the time between two dates?** Yes. Use the second calculator on this page, or the days between dates tool, to count the days, weeks, weekdays and working days between any two dates. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://calendarbest.com"},{"@type":"ListItem","position":2,"name":"Tools","item":"https://calendarbest.com/tools"},{"@type":"ListItem","position":3,"name":"Date Calculator","item":"https://calendarbest.com/tools/date-calculator"}]} ``` ```json {"@context":"https://schema.org","@type":"FAQPage","mainEntity":[{"@type":"Question","name":"How do I add days to a date?","acceptedAnswer":{"@type":"Answer","text":"Enter the start date, choose Add, type the number of days and leave the unit on days. The calculator moves forward one calendar day at a time, so 90 days after January 1, 2027 is April 1, 2027. To go back in time, choose Subtract."}},{"@type":"Question","name":"What happens when I add a month to January 31?","acceptedAnswer":{"@type":"Answer","text":"Months have different lengths, so the result moves to the last day of the shorter month: January 31 plus one month is February 28 (or February 29 in a leap year). Adding a year to February 29 gives February 28."}},{"@type":"Question","name":"What counts as a business day?","acceptedAnswer":{"@type":"Answer","text":"Monday to Friday, excluding US federal holidays on their observed dates. If you start on a weekend or holiday, adding one business day gives the next working day."}},{"@type":"Question","name":"How many weeks are in a year?","acceptedAnswer":{"@type":"Answer","text":"A year has 52 weeks plus one day, or plus two days in a leap year. In the ISO week system some years, such as 2026, have 53 numbered weeks."}},{"@type":"Question","name":"Can I calculate the time between two dates?","acceptedAnswer":{"@type":"Answer","text":"Yes. Use the second calculator on this page, or the days between dates tool, to count the days, weeks, weekdays and working days between any two dates."}}]} ``` ```json {"@context":"https://schema.org","@type":"WebApplication","name":"Date Calculator","url":"https://calendarbest.com/tools/date-calculator","applicationCategory":"UtilitiesApplication","operatingSystem":"Any","browserRequirements":"Requires JavaScript","offers":{"@type":"Offer","price":"0","priceCurrency":"USD"}} ``` ```json {"@context":"https://schema.org","@graph":[{"@id":"https://calendarbest.com/#website","@type":"WebSite","description":"Free calendar-to-PDF generator with a visual builder. Design monthly or yearly calendar layouts and export high-quality PDFs.","inLanguage":"en","name":"CalendarBest","url":"https://calendarbest.com/","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://calendarbest.com/builder?q={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"publisher":{"@id":"https://calendarbest.com/#identity"},"workTranslation":[{"@id":"https://calendarbest.com/de#website"},{"@id":"https://calendarbest.com/fr#website"},{"@id":"https://calendarbest.com/es#website"},{"@id":"https://calendarbest.com/it#website"},{"@id":"https://calendarbest.com/pt#website"}]},{"@id":"https://calendarbest.com/tools/date-calculator#webpage","@type":"WebPage","description":"Free date calculator. Add or subtract days, weeks, months, years or business days from any date, and count the days between two dates. Business days skip US federal holidays.","name":"Date Calculator: Add or Subtract Days From a Date","url":"https://calendarbest.com/tools/date-calculator","isPartOf":{"@id":"https://calendarbest.com/#website"},"potentialAction":[{"@type":"ReadAction","target":["https://calendarbest.com/tools/date-calculator"]}],"primaryImageOfPage":{"@id":"https://calendarbest.com/#logo"}},{"@id":"https://calendarbest.com/#identity","@type":"Organization","description":"Free calendar-to-PDF generator with a visual builder. Design monthly or yearly calendar layouts and export high-quality PDFs.","name":"CalendarBest","url":"https://calendarbest.com","logo":{"@id":"https://calendarbest.com/#logo"}},{"@id":"https://calendarbest.com/tools/date-calculator#/schema/software-application/1","@type":"SoftwareApplication","applicationCategory":"DesignApplication","name":"CalendarBest","operatingSystem":"Web","offers":{"@type":"Offer","availability":"https://schema.org/InStock","price":0,"priceCurrency":"USD","priceValidUntil":"2027-12-30T00:00:00.000Z"}},{"@id":"https://calendarbest.com/#logo","@type":"ImageObject","caption":"CalendarBest","contentUrl":"https://calendarbest.com/logo.png","inLanguage":"en","url":"https://calendarbest.com/logo.png"}]} ``` ## Sitemap See the full [sitemap](https://calendarbest.com/sitemap.md) for all pages.