Date & Time Calculators

6 professional tools. Calculate ages, date differences, business days, and countdowns with date and time tools.

What Is Date & Time?

Date and time calculators handle calendar arithmetic — ages, durations, business days, and countdowns. Essential for project planning, legal deadlines, HR, and event management.

Core Topics

Age & Dates

Calculate exact age and date offsets.

Time Arithmetic

Add and subtract hours and minutes.

Business Days

Exclude weekends for SLA and finance.

All Date & Time Calculators

ToolLink
AgeAge Calculator
DateDate Calculator
TimeTime Calculator
Days Between DatesDays Between Dates
Business DaysBusiness Days Calculator
CountdownCountdown Calculator

Key Concepts

  • Calendar days include all days; business days exclude weekends (and optionally holidays).
  • Leap years add February 29 every 4 years (with century exceptions).
  • Time zones affect absolute timestamps — specify UTC when collaborating globally.
  • Inclusive vs exclusive end dates change day counts by one.
  • ISO 8601 format (YYYY-MM-DD) avoids US/EU date ambiguity.

Common Mistakes

  • Off-by-one errors on inclusive/exclusive date ranges
  • Ignoring leap years in long spans
  • Mixing 12-hour and 24-hour time formats
  • Assuming all countries share the same holiday calendar

Frequently Asked Questions

Weekends (Saturday and Sunday) are excluded by default. Add custom holiday lists for locale-specific rules.

Yes. Age is computed from exact calendar dates, including leap day adjustments.