100 Day Calculator
Plan goals, celebrations, or deadlines exactly 100 days from any starting point.
Start date: Tuesday, November 25, 2025
100 days later: Thursday, March 5, 2026
Time span: 100 days ≈ 14.3 weeks ≈ 3.3 months
Days from today: 100 day(s) remaining
How to Use This Calculator
Choose a start date
Pick the day an initiative begins or an event occurred.
Select direction
Look ahead 100 days to plan milestones or look back 100 days to review progress.
Share the date
Use the calculated day for project timelines, accountability groups, or celebration planning.
Formula
Target Date = Start Date ± 100 days
Weeks ≈ 100 ÷ 7
Months ≈ 100 ÷ 30.4375
Example: Start 2025-11-09 → 100 days later is 2026-02-17 (Tuesday).
Why 100 Days Matters
- Break large goals into a manageable 100-day sprint.
- Celebrate baby’s 100-day milestone or 100 days sober.
- Plan academic terms, leadership evaluations, or product launches.
- Measure habit streaks and quarter-long initiatives.
Frequently Asked Questions
Does the calculator account for leap years?
Yes—adding days uses the native calendar, so February 29th is included when applicable.
Can I calculate business days instead?
This tool uses calendar days. For business days, use the Business Days Calculator.
How can I set reminders?
Add the target date to your calendar and set milestone alerts (30, 60, 90 days) for check-ins.
Can I share the result?
Copy the output date and details into your project docs or group chats to keep everyone aligned.