From notice periods and contract deadlines to project milestones and holiday countdowns — this free calculator tells you the precise number of calendar days, weeks, and months between any two dates.
Select your start and end dates and click Calculate. Results are instant. No sign-up, no data stored.
Find the exact number of days, weeks and months between any two dates
Select your start date and end date, then click Calculate. You instantly see the exact number of calendar days between the two dates, broken down into weeks and approximate months. The calculator handles any date range including across different years and through leap years.
This type of calculation comes up constantly in professional and personal contexts. HR professionals use it to verify notice periods — typically one week per year of service up to a maximum. Lawyers and solicitors use it for contract deadlines, appeal windows (21 days is common), and limitation periods. Project managers use it for milestone planning and sprint calculations. Individuals use it to count down to holidays, anniversaries, or important events.
Finance teams use it for invoice payment terms — net 30, net 60, or net 90 days from invoice date. Landlords and tenants use it to calculate notice periods for tenancy agreements. And anyone dealing with HMRC deadlines, insurance renewal dates, or warranty periods will find it useful.
This calculator counts the number of calendar days from the start date up to but not including the end date. This is the standard method used in most legal and HR contexts. To include both the start and end date in your count, add 1 to the result. The calculator correctly handles leap years when calculating across February.
Last updated: May 2026