Days Between Dates & Add / Subtract Time
Find the exact number of days, weeks, months, or years between any two dates — or add and subtract time from a date instantly. Runs entirely in your browser, nothing is sent to a server.
Counting days sounds simple until you hit a month with 28 days instead of 30, or a leap year that adds one back in. This calculator uses the actual Gregorian calendar — not a fixed 30-day-month approximation — so results stay accurate across February, leap years, and year boundaries.
Adding a month to a date isn't always the same number of days. "One month from January 31" is commonly interpreted as February 28 (or 29 in a leap year), since February has no 31st day — the month rolls forward and the day clamps to the last valid date. This calculator follows that convention.
Business day counts exclude Saturdays and Sundays. This matters for contract deadlines, payment terms, court filing windows, and any situation where a document specifies "business days" rather than "calendar days" — always check which one applies to your situation before relying on a count.
Common uses include calculating a 30-, 60-, or 90-day deadline from a contract start date; working out a project timeline in weeks; finding out how many days until a birthday, anniversary, or event; or confirming whether a lease or warranty is still in effect. If you need to calculate hours and minutes between two clock times, use the time duration calculator instead.
Each mode is built for a different way people actually ask "what date is that" — pick the one that matches what you're trying to do.
The exact days, weeks, and months between any two dates.
Pick a start date and an end date and get the total day count instantly, broken down into years, months, and days, plus a separate weeks-and-days count. Business days and the day of the week for each date are included by default, not hidden behind an extra click.
Add or subtract days, weeks, months, or years from any date.
Enter a starting date, a duration, and a unit, then add or subtract — the resulting date appears instantly. Correctly handles month-length differences, so adding one month to January 31 rolls forward to February 28 (or 29 in a leap year) instead of returning an invalid date.
Instant answers for common intervals like 30, 60, or 90 days from today.
One-click chips for the most common intervals people search for, plus a custom field for any amount in days, weeks, or months. Results compute instantly from today's date with no page reload — click a preset or type your own and get a real date back immediately.
Real feedback from people who use these tools regularly.
Open the "Days between" tab, pick a start date and an end date, and the total number of days appears immediately — broken down into years, months, days, and weeks. Business days and the day of the week for each date are shown automatically.
Use the "Quick shortcuts" tab and click the "30 days" chip — the result date is calculated from today's date instantly. You can also use the "Add/subtract" tab: set today as the start date, enter 30, choose "days", and hit Add.
Open the "Quick shortcuts" tab and click the "90 days" chip. The exact date 90 calendar days from today will appear immediately, including the day of the week.
It depends on which 3 months. Three calendar months can be 89, 90, 91, or 92 days depending on whether February or a 31-day month is included. Use the "Days between" tab with your specific start date to get the precise count for your situation.
Open the "Add/subtract" tab, enter your starting date, type the number of days you want to add, make sure "days" is selected as the unit, and click Add. The resulting date appears immediately, corrected for month lengths and leap years.
No. The result is the number of days from the start date up to but not including the end date — the same convention used for lease terms, age calculations, and most legal deadlines. If you need an inclusive count, add one day to the result.
Calendar days count every day including weekends. Business days exclude Saturdays and Sundays. Contract deadlines, payment terms, and legal filing windows often specify one or the other explicitly — check the relevant document before assuming.
Use the "Days between" tab — the result automatically includes a weeks-and-days breakdown alongside the total day count. For example, 90 days displays as 12 weeks and 6 days.
Months have different lengths. Adding one month to January 31 can't land on February 31 since it doesn't exist — this calculator rolls forward to the last valid day of the target month (February 28, or 29 in a leap year).
No. All calculations run locally in your browser using JavaScript. Nothing about the dates you enter is transmitted or stored anywhere.
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