Ultimate Date Calculator: Calculate Age, Durations, and Deadlines

Simple Date Calculator: Find Future or Past Dates in Seconds

What it is
A lightweight tool that lets you add or subtract days, weeks, months, or years from a given date to instantly find a future or past date.

Key features

• Add/subtract days, weeks, months, years — enter a start date and an offset (e.g., +45 days, -3 months).
• Quick presets — common offsets like +7 days, +30 days, +1 year.
• Workday option — skip weekends (and optionally custom holidays) when calculating business days.
• Automatic leap-year handling — correctly accounts for Feb 29 and month-length differences.
• Time-unit conversions — convert between days, weeks, months, and years for planning.
• Simple UI — minimal inputs: start date, operation (+/−), amount, unit; result displays immediately.
• Copy/share result — copy date string in common formats (YYYY‑MM‑DD, MM/DD/YYYY, ISO).

How to use (quick steps)

1. Enter the start date (or choose “today”).
2. Select add or subtract.
3. Enter the amount and choose unit (days, weeks, months, years).
4. (Optional) Enable “workdays only” and add holiday dates.
5. Read the resulting date and copy it in your preferred format.

Use cases

• Scheduling events or deadlines.
• Calculating due dates and follow-ups.
• Planning project timelines and milestones.
• Determining expiration or renewal dates.
• Figuring ages or anniversary dates.

Limitations to watch

• Month-based arithmetic can be ambiguous (adding one month to Jan 31 → Feb ⁄₂₉); the tool should document its rule (usually clamp to last day of target month).
• Time zones and time-of-day specifics may not be handled by the simplest versions.

If you want, I can provide sample UI text, a short algorithm for month handling, or five microcopy lines for buttons and labels.