Anniversary calculator
Find milestones and yearly anniversaries
How it works
Find 100-day milestones and yearly anniversaries. Counting the start as day 1 places day 100 at 99 days later. February 29 anniversaries clamp to the last day of February.
Example
Starting January 1, 2026 as day 1 gives April 10 as day 100.
How to use
- Enter your values or choose a local file.
- Choose settings and run the tool.
- Review the result, then copy it or download the file.
Common questions
What rules does this tool use?
Find 100-day milestones and yearly anniversaries. Counting the start as day 1 places day 100 at 99 days later. February 29 anniversaries clamp to the last day of February.
Are my inputs uploaded?
Calculations, texts and files are processed in this browser. The currency tool requests only currency codes from our server.
Free tool · Inputs processed locally · Updated October 5, 2026