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Add Days to Date Calculator

The date a number of calendar or business days from a start date.

By CalcHub Editorial · Last reviewed

Quick answer

  • Formula: Result = start date + N days (calendar mode counts every day; business mode steps over weekends only)
  • Worked example — Resulting date: March 14, 2026 (full example below).

Add Days to Date Calculator

Worked example result
Resulting dateMarch 14, 2026
Resulting date (ISO)2026-03-14
Day of the weekSaturday

Four calendar days after Tuesday, March 10, 2026 is Saturday, March 14, 2026. In business-day mode the same step lands on Monday, March 16.

Diagram: how the Add Days to Date Calculator works — you enter Start year, Start month (1–12), Start day, Days to add (negative subtracts), Counting mode; it applies the formula Result = start date + N days (calendar mode counts every day; busin…; and the worked example gives Resulting date: March 14, 2026.
How the Add Days to Date Calculator works — the inputs, the formula, and a worked example (Resulting date: March 14, 2026).

Add or subtract days from any date and get the resulting date and its day of the week. Negative numbers of days move backwards.

Switch the mode to business days to skip Saturdays and Sundays — the mode used for delivery estimates, notice periods and processing times quoted in working days.

The formula

Result = start date + N days (calendar mode counts every day; business mode steps over weekends only)

Worked example

Four calendar days after Tuesday, March 10, 2026 is Saturday, March 14, 2026. In business-day mode the same step lands on Monday, March 16.

Worked example for the Add Days to Date Calculator: with Start year 2026, Start month (1–12) 3, Start day 10, the result is Resulting date: March 14, 2026; Resulting date (ISO): 2026-03-14.
The worked example, with the example values entered and the results they give.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

How does business-day mode handle a weekend start?

It steps forward (or backward) one calendar day at a time and only counts Monday–Friday landings, so starting on a Saturday, +1 business day gives the following Monday.

Can I subtract days?

Yes — enter a negative number of days and the calculator moves backwards from the start date.

Category: Date & Time calculators

Sources & methodology

This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.

Content last reviewed by CalcHub Editorial.

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