How to use the date calculator
- Pick Days between two dates or Add or subtract a period.
- Enter the start date.
- Enter the end date or the period you want to add.
- Press Calculate.
- Read the day and week totals plus months and working days.
What this date calculator gives you
- Days, weeks and months between any two dates.
- A workday count with Saturdays and Sundays removed.
- The gap in years, months and days.
- Any mix of days and weeks plus months and years added or taken away.
- The weekday of each date for deadline checks.
- Private math in your browser with no upload.
Why date math is harder than it looks
A day count sounds easy. Then leap years and uneven months show up. February has 28 days except when it has 29. One month after 31 January has no obvious answer. Daylight saving also shifts clock times by an hour twice a year.
This date calculator avoids the last problem. It counts whole calendar days and not hours. That matches what people mean when they ask how many days apart two dates sit.
Do you count the first day?
This trips people up all the time. It can matter in law too. Monday to Friday is four days if you count the gaps. It is five days if you count each day itself.
This tool counts the gaps. Does your contract count the start day too? Add one to the result. A deadline of "within 5 days" often means five full days after the start. Read how the contract defines it. Both styles are common.
What the date calculator workday count misses
The working day count removes Saturdays and Sundays. It does not remove public holidays. Those differ by country, by state and by year.
| Where | Holidays to subtract |
|---|---|
| US federal offices | 11 federal holidays a year |
| US private employers | Varies by company and state |
| England and Wales | 8 bank holidays a year |
| Contracts | Read the definition of business days |
Use the figure as a starting point. Then adjust for the calendar that applies to you.
Month math has no single right answer
Take 31 January plus one month. Some systems give 28 February. Others give 2 or 3 March. Some throw an error. A 29 February date plus one year can land on 28 February or 1 March.
This tool clamps to the end of the target month. So 31 January plus one month gives 28 February. It gives 29 February in a leap year. Most spreadsheet apps follow the same rule. Does a legal deadline hang on it? Confirm which rule applies.
Where a date calculator helps
- Notice periods for a job or a lease.
- Project timelines and sprint plans.
- Visa stays and passport validity checks.
- Warranty and return windows.
- Pregnancy due dates and school start dates.
- Countdowns to trips, weddings and holidays.
A quick date calculator example
Your lease ends on 31 December. The landlord needs 60 days of notice. Pick add or subtract mode. Enter 31 December and subtract 60 days. The tool shows 1 November and the weekday it falls on. Send your notice on or before that day to stay safe.
Common date calculator questions
Can I enter the dates in either order?
Yes. The tool swaps them and tells you. You always get a positive result.
Why does the month count look short?
The tool counts complete months only. Leftover days show in the days field.
Tips for deadline math
- Write down whether your count includes the start day.
- Subtract holidays by hand for workday counts.
- Check the weekday of the final date.
- Move a weekend deadline to the day the rules say.
Many courts and agencies push a deadline that lands on a weekend to the next business day. Others do not. A quick check of the rules saves a missed filing. The weekday line in the results makes that check easy.
Who uses a date calculator?
Office workers plan deadlines. HR teams count leave days. Travelers check visa limits. Students count down to exams. Lawyers check filing windows.
Your dates stay private
The tool runs in your browser. Contract dates and personal plans never leave your device. Need an exact age? Use the age calculator. Want to add up hours? Try the time calculator. Need to read a Unix date? The timestamp converter helps.