Date Calculator
Days between two dates in years, months and days — or add and subtract days from any date — with leap years handled exactly.
Pick both dates to see the difference.
This tool runs entirely in your browser. Your data never leaves your device — it is not uploaded to any server.
How to use
- 1Choose Difference between dates, or Add / subtract days.
- 2Enter the two dates — or a base date and a day count.
- 3Read the exact breakdown and the resulting date with its weekday.
Date Calculator
Two everyday date problems in one place: measure the gap between two dates (calendar-accurate y/m/d, total days, weeks and leftover days), or walk N days forward or backward from a base date and get the resulting date with its weekday.
Because the arithmetic is true calendar math — not an average month — a leap-day birthday, a 31-day month or a February span all come out exactly right, with no server involved.
Frequently asked questions
How is the years/months/days difference computed?
The same way people count anniversaries: full years, then full months, then leftover days measured against the real lengths of the months involved. The 29th of February is treated as the last day of February, so spans across leap years stay honest.
Does “add 90 days” mean business days?
No — the day count is calendar days, including weekends. For contract deadlines that count business days, add roughly 5 days per week of span as a first approximation, or use a dedicated business-day tool.
Are the dates I enter sent anywhere?
No. Both modes run entirely in your browser using JavaScript's date arithmetic; nothing is uploaded and nothing is stored.
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Embed this tool
Put this tool on your own site with one line — it runs entirely in the visitor's browser.
<iframe src="https://zoyku.com/en/tools/date-calculator?embed=1" width="100%" height="640" style="border:0;border-radius:16px" title="Zoyku — date-calculator" loading="lazy"></iframe>