How the date difference calculator works
Last updated 10 November 2026
How many days until a deadline, or since a start date? This calculator gives the answer in several forms.
How it works
- Whole months are counted forward from the first date. A day past the end of a month counts as that month’s last day.
- The leftover days are counted from there.
Questions it answers
Dates come up in many everyday sums: how long until a deadline, how long since someone started a job, how many days are left on a lease notice. Pick two dates and the calculator shows the gap in several forms at once.
- Total days between the dates
- Whole weeks and leftover days
- Years, months and days, the way people usually say it
- Approximate working days, Monday to Friday
Counting months and days
Months are counted forward from the earlier date. If the later date falls on a day that does not exist in a month, such as the thirty-first in a short month, it is treated as the last day of that month. The days that are left over after the whole months are shown separately.
Including or leaving out the end date
Counting the gap between Monday and Wednesday gives two days if you count the steps, or three if you count every day you touch. Contracts and notice periods sometimes use the second way. This tool counts the steps between dates, so add one if the rule you are following counts both the first and the last day.
Public holidays
The working-day count looks at weekdays only. It does not know about public holidays, school holidays or company closures, because these change from year to year and by organisation. Subtract those days yourself if they matter.
Privacy
The dates you pick stay in your browser. They are not sent anywhere or stored.
A short example
Say a lease runs from the start of one month to the end of a later month. Enter both dates and read the answer in months and days for the lease term, and the total days if you need to pro-rate rent. The weekday count is useful for rough project planning, where only working days matter.
Related tools
For a person's age use the age calculator. To count down to a date that is coming up, use the exam countdown or the tax year countdown.
Common uses
- Notice periods and lease terms
- Warranty and return windows
- Project timelines and delivery dates
- Counting days between two payments to work out a daily rate
Dates from your device
The tool does not look anything up. It only does arithmetic on the two dates you choose, so it works offline once the page has loaded. Both dates are treated as whole calendar days, with no time of day involved.
Things to watch
- If you swap the dates, the answer is the same.
- Check the end-date rule if you need to include both days.
Nothing is stored.
Like every tool on MoneyMzansi, this one runs entirely in your browser. There is no account, no upload and no sign-up, so it keeps working even if your connection drops once the page has loaded.