Date and time calculations made simple
Work out date differences, working days, time durations, ages, deadlines and time zones — accurately, and without signing up for anything.
Popular calculators
-
Date Difference Calculator
Find the exact gap between two dates in every useful unit.
-
Days Between Dates Calculator
Count the days between two dates, with a full weekday breakdown.
-
Add or Subtract Days from a Date
Add or subtract days, weeks, months or years from any date.
-
Time Duration Calculator
Measure the time between two clock times, even past midnight.
-
Hours Worked Calculator
Work out paid hours from a shift, after unpaid breaks.
-
Working Days Between Dates
Count business days between dates, excluding holidays.
-
Add Working Days to a Date
Move forward or back by working days, skipping holidays.
-
Time Zone Converter
Convert a time between any two cities, with DST handled.
-
Meeting Time Planner
Find meeting slots that work across several countries.
-
Exact Age Calculator
Calculate an exact age in years, months and days.
Quick date difference
Two dates, every useful unit. For the full version with weekday breakdowns and the option to include the end date, open the date difference calculator.
Browse by category
-
Date Calculators
Add, subtract, compare and identify dates.
-
Time Calculators
Calculate durations, hours, shifts and timesheets.
-
Business Day Calculators
Calculate working days, deadlines and notice periods.
-
Time Zone Calculators
Convert times and plan international meetings.
-
Age and Event Calculators
Calculate ages, anniversaries and countdowns.
-
Developer Date Tools
Convert timestamps, UTC values and date formats.
Why use this site
- Free to use
- No account required
- Works on mobile
- Methods explained on every page
- International dates and holidays
Every calculator explains how it reaches its answer, states whether endpoints are counted, and says which holiday calendar and time zone data it used. Where a result depends on a convention that is not universal — leap-year birthdays, substitute bank holidays, the hour skipped when clocks go forward — the page says so rather than quietly picking one.
Guides and explanations
-
How working days are calculated
Why weekends, substitute bank holidays and endpoint counting change the answer, and how to get it right.
-
Understanding ISO week numbers
Why 1 January can fall in week 53 of the previous year, and which years have 53 weeks.
-
How daylight saving affects calculations
The hour that never happens, the hour that happens twice, and why recurring meetings drift.
-
How to calculate hours worked
Night shifts, unpaid breaks, decimal hours, and the rounding rules that quietly cost money.