Date Diff + Age Calculator

Compute date differences, ages, business days, and anniversary countdowns — timezone-aware, with custom holiday exclusion.

⚡ 100% client-side · no upload · works offline

From / To

From (local date/time)

To (local date/time)

Timezone (display only)

Result

Duration

—

Total days

—

Total hours

—

Total minutes

—

Total seconds

—

Years + months + days (calendar)—

Weeks

—

Total days—

Birthday

Birth date (your time zone)

"As of" date (defaults to today)

Age

Current age

—

Total days lived

—

Total weeks

—

Total hours

—

Next birthday

—

Range + rules

From

Weekend days (excluded)

Saturday Sunday Friday

Exclude holidays (one per line: YYYY-MM-DD, or MM-DD for annual)

Result

Business days

—

Calendar days

—

Days excluded

—

Weeks (approx)

—

Add an anniversary

Saved locally in your browser. Use for personal reminders — events repeat yearly on the same date.

Upcoming

No anniversaries yet. Add one above.

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