Date Calculator

Count the days between two dates, or find the date 30, 60 or 90 days from now — in one click.

What is this tool?

Date math runs everyday American life: a contractor's 45-day payment window, a 90-day probationary period at a new job, a return deadline, a visa or passport timeline, or counting down to a due date or wedding. Doing that math by hand invites off-by-one mistakes, especially across month boundaries and leap years. This date calculator handles both jobs — days between two dates, and adding or subtracting days from a starting date.

Project managers use it to sanity-check schedules, HR teams use it for benefit eligibility dates, and travelers use it to make sure a passport's six-month validity rule is satisfied. Pick your dates in MM/DD/YYYY format and the answers are exact, because the calculator works with real calendar dates rather than approximations like 30-day months.

How to use it

1. To count days: pick a start date and an end date, then click Count days.
2. To add or subtract: pick a start date, enter a number of days, choose add or subtract, then click Find the date.
3. Both tools are independent — use either or both.

Formula & method

Worked example

From January 15 to April 15, 2026 is exactly 90 days — a clean way to verify a 90-day window. And 60 days after March 1, 2026 is April 30, 2026, because March has 31 days.

Frequently asked questions