Date Difference Calculator — Free Online Tool
Count days, weeks, months & years between any two dates. · No signup · Works on mobile
100% private: your data is processed in your browser. Nothing is uploaded to our servers.
How to use the date difference calculator
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Pick your start date and end date from the calendars.
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Choose whether to include the end date in the count (useful for rentals and deadlines).
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See total days plus the years/months/days breakdown, and total weeks and hours.
What does this tool do?
This free date difference calculator counts the exact time between any two dates — in total days, and broken down into years, months, and days. It handles leap years automatically and lets you include or exclude the end date, which matters for deadlines, contracts, and billing periods.
How does the date difference calculator work?
The tool converts both dates to calendar-aware timestamps and computes the difference two ways: total elapsed days (simple subtraction), and a calendar breakdown that counts whole years, then whole months of their true lengths, then remaining days.
Frequently Asked Questions
Why do some tools give a different number of days between the same dates?
The difference is almost always end-date inclusion. From 1 Jan to 10 Jan is 9 days elapsed, but 10 days if you count both endpoints — hotels count nights (exclusive) while car rentals often count days (inclusive). This calculator has a toggle so you get the number you actually need.
How are months counted when they have different lengths?
The calculator counts whole calendar months from the start date's day-of-month: 31 Jan to 28 Feb counts as 28 days (not 1 month) in strict mode, while 15 Jan to 15 Feb is exactly 1 month. Leftover days use the actual month lengths, with leap-year February handled automatically.
Is the date difference calculator really free?
Yes — 100% free with no hidden charges, trial limits, or premium tiers for core features. You don't need to create an account or enter an email address. The site is supported by non-intrusive display ads, which keeps every tool free for everyone.
Is my data private when using the date difference calculator?
Completely. The date difference calculator runs entirely in your browser using JavaScript — nothing you type or upload is sent to our servers. When you close the tab, your data is gone. This makes it safe for confidential documents, financial figures, and personal information.
Does the date difference calculator work on mobile phones?
Yes. The date difference calculator is built mobile-first and works on any phone or tablet with a modern browser — iPhone (Safari), Android (Chrome), and everything in between. The layout adapts to small screens, so buttons and inputs stay easy to tap on a 375px-wide display.
Do I need to install anything to use the date difference calculator?
No. The date difference calculator works directly in your web browser — no downloads, no extensions, no signup. Just open the page, use the tool, and get your result instantly. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.