Add or Subtract Days Calculator
Add or Subtract Days Calculator by NIVITA HUF. Model scenarios, review calculations, explore detailed breakdowns and export results. Useful free planning tool.
Set your assumptions
Update the values to calculate your scenario.
Your calculation
Results update as you enter information.
JavaScript is required for interactive calculations.
How this calculator works
New calendar date = start date plus the selected integer number of days.
Important assumptions
Date arithmetic counts actual UTC calendar days, not business days.
About the Add or Subtract Days Calculator
What inputs are needed for the Add or Subtract Days Calculator?
The calculator supports Start date; End / reference date; Days to add / subtract; Weekend days; Holidays (optional YYYY-MM-DD per line); Start hour (0–23). You can change each applicable input and immediately recalculate.
How does the Add or Subtract Days Calculator calculate its results?
New calendar date = start date plus the selected integer number of days.
Can I save or share my calculation?
Yes. Use Export CSV for the results table, Copy results for a summary, Share scenario for an input-preserving link, or Print to keep a copy. No sign-in is needed.
Are calculator results guaranteed?
No. Calculations depend on the values entered and the assumptions shown. Financial products and regulatory rules can change, and investment projections do not guarantee returns.