How many days between two dates?
Deadlines, contract periods, visa days, invoice terms, “how old is this, exactly?” — all the same little calculation, and all easy to get wrong by one. This does it with calendar arithmetic, leap years included, and tells you whether the end day is being counted.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Pick the two dates. The count updates as you choose.
- Decide whether the last day counts: “+1” includes both end days, which is how hotel nights differ from rental days.
- Use the lower box for the other direction: a date plus or minus a number of days, with the weekday of the result.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see fetch the tool’s own code — and, for a few heavy tools, their open-source engine from a public CDN — plus one small page-view ping to loreatec.jp (page address and title, nothing more). None of them carry your file.
Frequently asked questions
Is the end date included in the count?
By default no: from the 1st to the 3rd is 2 days, the same way most deadlines and interest calculations work — and the way Japanese law counts periods, where the first day is normally excluded (初日不算入). Tick “+1” and both end days count, which is what you want for “days the equipment was on site” or an all-inclusive booking. The tool shows which convention it is using, so the off-by-one stays visible instead of hiding in the result.
Why does it also show years, months and days — is that not the same number?
No, and the difference is the point. “90 days” and “3 months” only coincide sometimes: months are 28 to 31 days long, so a 3-month contract from 15 January ends on a different day than one of 90 days. The tool gives both readings — total days for anything financial, the calendar span for anything contractual — so you can quote whichever the document actually says.
Are leap years and summer time handled?
Yes, structurally. Dates are compared as whole calendar days, not as 24-hour blocks, so the 23-hour and 25-hour days around clock changes cannot shift the count, and 29 February is just another day that either falls in the range or does not. This is exactly the class of bug that dividing timestamps by 86 400 000 produces, and the reason this tool does not do that.
Can it count working days?
It splits the total into Monday-to-Friday and weekend days, which answers most of it. Public holidays are a per-country matter and this page stays generic — if what you need is Japanese business days with the official holiday calendar, the Japanese-era date converter on this site has exactly that panel.
Is anything sent anywhere?
No. It is calendar arithmetic inside this tab; the page works with the connection off. The dates you type — which can be as personal as birthdays and contract terms get — are not seen by anyone.