Contract deadlines, countdowns, project lengths, 'how long until': the gap between two dates comes up constantly and mental math always misses by a day.
Updated August 15, 2026, after a fresh review, with updated visuals and links.
Pick start and end above, optionally include the end day (deadlines usually count it), and get the answer in days, weeks and months at once.
Reading the result
Pure days is the lawyer's number: January 1 to January 31 is 30 days, or 31 with the include-end-day box ticked. Rental periods and notice periods care about exactly this distinction.
Weeks and days help for nesting schedules: 90 days out is 12 weeks and 6 days, which maps cleanly onto sprint calendars and pregnancy trimesters alike.
The months figure is an average (30.44 days per month), because calendar months vary from 28 to 31 days: use it for feel, the day count for contracts.
Worth remembering
- Counting backward from a deadline: set the deadline as end date and today as start, re-check weekly as it shrinks.
- Visa and warranty windows often exclude the start day: read the wording, then tick the include-box accordingly.
Frequently asked
How many days are between two dates?
Subtract them as calendar dates: the difference in whole days excludes the start day by default. The include-end option adds one day, matching most deadline conventions.
How many days until a specific date?
Set start to today (the tool pre-fills it) and end to your target: the answer updates instantly every day you check.
