Tiny tools for everyday date math

Add/Subtract Business Days

Add or subtract a number of business days from a start date. Optionally exclude weekends (default) and your own holidays.

Holidays are treated as non‑business days.
› How this is calculated
We start from the given date at local noon and step forward (for positive numbers) or backward (for negative) one day at a time. A step is counted when the date is not a weekend (if excluded) and not in your holiday set. Adding 0 days returns the start date.

Examples

  • Contract lead time: Add 30 business days to 2025‑10‑03 excluding weekends.
  • Backdate: Subtract 10 business days from 2025‑11‑14 including custom holidays.