Add or Subtract Days from a Date

Use this calculator whenever you need to shift a single date forward or backward by a calendar amount—days, weeks, or months—counting every calendar day rather than business days only.

Choose a start date, whether to add or subtract, and an amount in days, weeks, or months. Weeks are converted to 7-day steps; months move by calendar month with end-of-month clamping (for example, January 31 plus one month becomes February 28 or 29).

All calculations use UTC midnight dates. For counting working days only, use the Business Days Calculator. To measure the span between two dates, try Days Between Dates.

Start date: 1 June 2025. Direction: add. Amount: 10 days.

Result: 11 June 2025.

For the same start date with 2 weeks subtracted instead, the result is 18 May 2025 (14 calendar days backward).

For 31 January 2025 plus 1 month, the result is 28 February 2025 (end-of-month clamping, since February 2025 is not a leap year).

The Business Days vs Calendar Days Guide explains when weekends and holidays count and which day type applies to deadlines, invoices, and contracts.

The How Business Days Are Calculated Guide and Business Days Between Dates Guide cover the counting rules behind every business-day tool on this site.

The Business Days Calculator and Working Days Calculator count weekdays between two known dates, excluding weekends and optional US federal holidays.

The Add Business Days To Date, Subtract Business Days From Date, and Business Day Offset calculators move a single date forward or backward by a business-day count.

The Business Days Until Date Calculator counts business days remaining from today or a custom date to a target deadline.

The Days Between Dates Calculator counts every calendar day between two dates, including weekends—use it instead of the business-day tools when weekends should count.

The Date Range Calculator and Date Duration Calculator break a range into calendar-day totals or a years/months/days breakdown, with inclusive or exclusive boundary options.

The Add or Subtract Days Calculator shifts a single date forward or backward by days, weeks, or months.

The Age Calculator applies the same calendar breakdown used by Date Duration to a birth date, expressed as years, months, and days.

The Hours Between Dates and Date Difference calculators measure elapsed time between two date-times down to hours, minutes, and seconds.

The Date Format Converter, Unix Timestamp Converter, and Timezone Converter handle format and zone conversion for a single instant rather than a span between two dates.