① Days between two dates
② Add / subtract days from a date
Date Calculator Guide
1
Difference: pick start/end dates and display mode (days/months/years)
2
New date: enter a start date and days to add/subtract (can be negative)
3
Click calculate; the new date shows its weekday
📅What it can do
- Days/months/years between two dates
- What date is N days later (e.g. in 100 days)
- What date was N days ago (enter a negative)
💡Tips
- "Today" quickly sets the date to the current day
- Great for anniversaries, countdowns and project timelines
- The new-date result includes the weekday for planning
Anniversaries, days-until and timelines all need day counting. This tool covers both difference and add/subtract, with weekdays.
🔒 Computed entirely locally in your browser, no data uploaded — no install, no signup.