What the Date Difference Calculator does
This tool counts how much time sits between two calendar dates. Pick a start date and an end date, and it tells you the exact number of days, plus the same gap shown in weeks, months, and years. It is handy for working out how many days until a deadline, the length of a project or contract, how old something is, a notice period, a due date, or simply how long ago an event happened.
It is built for quick everyday math, so the month and year figures are approximate (months use an average of 30.44 days, years use 365.25 to account for leap years). For anything legal, medical, or financial, treat the result as a guide rather than official advice.
How to use it
- Click the From date field and choose your starting date.
- Click the To date field and choose the ending date.
- Press Calculate.
- Read the results: total days in large type, then weeks, months (approx), and years (approx).
- Change either date to test a new scenario. The order does not matter, since the tool measures the absolute gap between them.
Why use this one
It runs entirely in your browser, so the dates you enter stay on your device and nothing is sent to a server. There is no sign-up, no cost, and no install. Results appear the moment you hit Calculate, and it works the same on a phone, tablet, or laptop.
A small tip: if you want the difference including today, set one date to today and the other to your target, then add or subtract a day depending on whether you count the start date itself.
If you regularly juggle lots of files alongside date math, the BulkPro desktop app from the same team (Bilgetek) handles batch jobs, while this page is best for a quick one-off calculation.
Frequently asked questions
- How do I count the number of days between two dates?
- Choose your start date in the From date field, choose your end date in the To date field, then click Calculate. The tool shows the total days right away, along with the equivalent weeks, months, and years.
- Does it matter which date I put first?
- No. The calculator measures the absolute gap between the two dates, so it gives the same result whether the earlier date is in the From field or the To field.
- Why are the months and years marked as approximate?
- Months and years vary in length, so the tool uses averages (30.44 days per month and 365.25 days per year, which accounts for leap years). The day count is exact, while months and years are close estimates for general use.
- Is my date information sent anywhere?
- No. The calculation happens entirely in your browser, so the dates you enter never leave your device. The tool is free, needs no sign-up, and works offline once the page has loaded.
Related calculators
Last updated: June 15, 2026