Date Duration Calculator

Calculate the number of days, weeks, months, or years between two dates. Also add or subtract any period from a date, and count business days excluding holidays.

How to Use

Type a date directly (MM/DD/YYYY) into either field, or click the calendar icon to use the date picker. Then click Calculate duration to see the result broken down into years, months, weeks, and days.

The calculator has three tabs:

• Duration — how long between two dates, broken down into years, months, weeks, and days
• Add / Subtract — what date is 90 days (or weeks, months, or years) from a given date
• Business Days — count working days between two dates, excluding weekends and US holidays

Common Uses

• Age calculation — how old is someone born on a specific date
• Project planning — how many days between kickoff and deadline
• Anniversary countdowns — days until or since a specific date
• Travel planning — duration of a trip
• Add / Subtract — what date is 6 months from today, or 100 days from a contract start date

Tips

• All three tabs share the same date inputs — switching tabs keeps your dates.
• The duration result shows the total in each unit independently (e.g. 400 days is also shown as 1 year, 1 month, 5 days).