Free Online Calculators
Days between dates, business days & countdown
Whether you're planning a trip, tracking a deadline, or figuring out how long until a big event, knowing the exact number of days between two dates is surprisingly useful. Simply enter a start date and an end date, and the calculator instantly shows you the total days, broken down into weeks, months, and even hours.
For example, if your project starts on March 1 and the deadline is April 15, the date duration comes out to 45 days — or 6 weeks and 3 days, or 1,080 hours. Having all those units at once helps you plan at whatever scale makes sense for your situation.
This kind of calculation gets tricky when you do it by hand, especially across month boundaries or leap years. February 2024 has 29 days, for instance, so counting manually from January 20 to March 5 is easy to get wrong. The calculator handles all of that automatically.
The countdown calculator feature is perfect for events with a fixed target date. Enter today as the start date and your goal date as the end — say, a wedding on December 20 — and you'll see exactly how many days (and weeks) you have left to prepare. It updates based on the current date so your countdown stays accurate.
The business days calculator is especially valuable for work and financial planning. It excludes Saturdays and Sundays from the total count. So if a contract says "delivery in 10 business days" starting Monday, May 5, the actual calendar deadline lands on Friday, May 16 — not May 15 as you might assume without accounting for the weekends in between.
Shipping estimates, invoice payment terms, legal notice periods, and HR onboarding timelines all commonly use business days rather than calendar days. Getting the right count matters. At simple-calculator.online, this tool makes it fast and mistake-free.
Beyond work deadlines, date duration calculations come up all the time in everyday life. Parents track how many days until school starts. Renters figure out how many days are left on a lease. Athletes count down days to race day. Knowing the number in multiple units — days, weeks, and months — gives you a fuller picture for scheduling and goal-setting.
For example, a 90-day fitness challenge starting January 1 ends on April 1. That's 12 weeks and 6 days, or roughly 3 months — useful to know when you're planning check-in milestones every 30 days. You can also work backwards: if your goal date is set, count back 30, 60, or 90 days to set earlier checkpoints.
By default, the calculator counts the gap between the two dates, so it excludes the start date and includes the end date. This matches how most deadlines and countdowns are interpreted — for example, "5 days from Monday" lands on Saturday.
Business days are Monday through Friday, excluding weekends. This calculator does not factor in public holidays, since those vary by country and region. If your situation requires holiday exclusions, add those manually to the result.
Yes. Enter any two dates regardless of order, and the calculator will return the duration between them. This is useful for things like calculating how long ago a contract was signed or how many days have passed since a specific event.