Date Calculator (Add / Subtract Days)

What date is N days from now?

This calculator answers questions like “what date is 90 days from today?” or “what was the date 45 days ago?”. Pick a starting date, choose whether to add or subtract, enter the number of days, and it returns the resulting date along with its day of the week.

It’s the tool for tracking deadlines that are defined in days rather than dates — a 30-day return window, a 90-day notice period, a 14-day trial, a payment due “net 60”, or a 21-day habit streak. Because it works on the real calendar, month lengths and leap years are handled for you.

How adding and subtracting days works

Counting forward or back by a number of days sounds simple, but doing it in your head is error-prone because months have 28, 30 or 31 days and February changes in leap years. The calculator steps through the real calendar one day at a time, so adding 40 days to 20 January correctly lands in early March, and the answer is always exact. It also tells you the resulting weekday, which matters when a deadline or appointment needs to avoid a weekend.

Everyday uses

• Returns and refunds — work out the last day of a 30- or 90-day return window.
• Notice periods — find the end date of a 30-, 60- or 90-day notice.
• Trials and subscriptions — see when a 7- or 14-day free trial converts to paid.
• Payment terms — calculate a “net 30” or “net 60” invoice due date.
• Health and habits — mark the end of a 21-day or 75-day challenge.

Counting forward versus the gap between dates

This tool answers “what date is N days away?”. If instead you already know both dates and want the number of days between them, use the date difference calculator. And if you’re counting down to a specific event rather than a fixed number of days, our guide on counting the days until any date walks through both approaches. For birthdays specifically, the birthday countdown does it in one step.