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Date Calculator — Days Between Dates & Add/Subtract Days

Calculate days between dates or add/subtract days, weeks, months, and years. Get totals in years, months, days, business days, and future/past dates instantly.

No uploads. Everything runs locally in your browser.

Date calculator for differences and add/subtract

Calculate the difference between two dates in years, months, days, totals, and business days. Add or subtract days, weeks, months, and years to find future or past dates. Works with leap years and month-end boundaries, all in your browser.

Private and fast: everything runs client-side. Supports Today and sample presets.

Date difference

Enter two dates and calculate to see the difference.

Add / subtract

Enter a base date and adjustments, then calculate to see the resulting date.

Benefits & use cases

  • Find days between dates for planning, deadlines, and compliance windows.
  • Add/subtract days, weeks, months, or years to project schedules and personal events.
  • See business-day counts for work estimates and SLAs.
  • Handle leap years and month-end rollovers reliably.

How date calculations work

We normalize both dates, compute calendar differences with borrowed days for month alignment, and count total and business days (Mon–Fri). Add/subtract applies years and months with end-of-month clamping, then weeks and days. Leap years and Feb 29 are handled so results stay accurate. All processing stays in your browser.

How to use Date Calculator

  1. Enter start and end dates, then Calculate Difference to see years/months/days, totals, and business days.
  2. Enter a base date with adjustments in days/weeks/months/years, then Calculate New Date to get the result.
  3. Use Today or sample presets, copy results, or clear to reset.

Key features of Date Calculator

  • Date difference with years, months, days, totals, and business-day count
  • Add or subtract days, weeks, months, and years to get a new date
  • Handles leap years and month-end rollovers
  • Copy results, clear quickly, and use Today/sample presets
  • Runs fully in your browser for privacy

Date Calculator — key benefits

  • Completely free with no signup or registration required.
  • Runs entirely in your browser — your data is never uploaded.
  • Works on desktop, tablet, and mobile devices.
  • Instant results with no waiting or processing queues.
  • Part of the ToolCircuit suite of free online utility tools tools.

FAQ

How is the date difference calculated?

We normalize both dates and compute calendar years, months, and days, plus total days/weeks and business-day count (Mon–Fri).

Can I add and subtract together?

Yes. Enter positive or negative numbers for days/weeks/months/years; the calculator applies them in order to return the final date.

Do you handle leap years and month-end?

Yes. Month and year additions clamp to the end of the target month (e.g., Jan 31 + 1 month → Feb 29/28 depending on leap year).

Are business days supported?

Yes. Business-day totals count Monday–Friday and exclude weekends (holidays not included).

Is any data uploaded?

No. All calculations run locally in your browser.

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