All calculators
Twenty-two focused date and time calculators, grouped by the question they answer. Every tool runs instantly in your browser.
What date and time calculators does Calcadian offer?
Calcadian has 22 free calculators across five groups: dates and differences, business and work time, time and duration, world and technical time, and age and personal dates. Each one runs in your browser, needs no sign-up, and works on mobile and desktop.
Calculators for HR and payroll teams
Need payroll hours, shift totals, employee tenure, business-day deadlines, probation dates, or time-zone planning? The HR calculator hub groups the relevant tools by common people-operations tasks.
Browse HR calculators →Dates and differences
Compare dates, move dates forward or backward, and measure calendar intervals.
Date Difference Calculator
Count days, weeks, months, and years between two dates.
Add or Subtract Days Calculator
Find a future or past date by adding or subtracting time.
Weeks Between Dates Calculator
Calculate total weeks, remaining days, and decimal weeks between two dates.
Months Between Dates Calculator
Count whole calendar months and the days left over.
Day of the Week Calculator
Find what day of the week any date falls on.
Business and work time
Calculate working days, work shifts, time cards and business-date rules.
Business Days Calculator
Count working days between two dates, excluding weekends.
Business Date Calculator
Add or subtract business days to find the resulting workday.
Weekly Time Card Calculator
Add up a full week of shifts with breaks and overtime.
Shift Calculator
Work out the hours in one shift, breaks included.
Decimal Hours Calculator
Convert between hours and minutes and decimal hours.
Time and duration
Work with clock times, durations, elapsed time and countdowns.
Time Duration Calculator
Calculate hours and minutes between two times.
Date & Time Difference Calculator
Measure elapsed time between two full date and time values.
Hours and Minutes Calculator
Add or subtract durations without base-60 arithmetic.
Time From Now Calculator
Find the local date and time a set duration from now.
Time Until Calculator
Count down to a future date and clock time.
Time Since Calculator
See how long ago a past date was, in years, months, and days.
World and technical time
Convert world time, technical timestamps and calendar week numbers.
Age and personal dates
Calculate ages, age gaps and time remaining until a date.
Which calculator should I use?
Match your question to a tool. If two tools could answer it, the one closer to your wording is usually the right choice.
| Calculator | Use when | You get |
|---|---|---|
| Date Difference | You have two dates and want the gap between them. | Days, weeks, months, years |
| Add or Subtract Days | You have one date and want to shift it forward or back. | A single resulting date |
| Weeks Between Dates | You want to know how many weeks span two dates. | Whole weeks plus remaining days, decimal weeks, total days |
| Months Between Dates | You want the answer in calendar months. | Complete months, remaining days, total days and weeks |
| Day of the Week | You need the weekday for a past or future date. | Weekday, day of year, ISO week |
| Business Days | You only want to count working days. | Workday count, excluding weekends + custom holidays |
| Business Date | You have one date and a number of working days. | The resulting workday, with skipped days listed |
| Weekly Time Card | You're adding up a whole week of shifts for payroll. | Daily and weekly hours, decimal hours, overtime, estimated pay |
| Shift Calculator | You need the hours in one shift, breaks included. | Hours worked, gross shift length, decimal hours |
| Decimal Hours | Payroll or a spreadsheet needs decimal hours. | Decimal hours, or hours and minutes back again |
| Time Duration | You're measuring hours and minutes inside a day. | Hours and minutes, with optional breaks |
| Date & Time Difference | Clock times matter, not just the dates. | Days, hours, minutes, and total hours |
| Hours and Minutes | You're adding or subtracting lengths of time. | Hours and minutes, decimal hours, total minutes |
| Time From Now | You want the clock time a set duration from now. | Local date and time, with the day it lands on |
| Time Until | You want a live countdown to a date and time. | Days, hours, minutes, seconds, ticking down |
| Time Since | You want the elapsed time since a past moment. | Years, months, days and running totals |
| Time Zone Converter | A time needs reading in another city. | Local time per city, offsets, day shift, meeting overlap |
| Unix Timestamp | You're working with epoch seconds or developer logs. | Local + UTC date, or a Unix timestamp |
| Week Number | You need the ISO week for a date. | Week number, week year, week range |
| Age | You need an exact age from a date of birth. | Years, months, days |
| Age Difference | You want the gap between two birth dates. | Years, months, days, and who is older |
| Days Until | You're counting down to a fixed future date. | Days remaining (or elapsed) |
What Calcadian is for
Calcadian is built for everyday planning: deadlines, trips, contracts, payroll periods, project timelines, age calculations, and the kind of "what date is X from Y" questions that come up at work or at home. The tools are accurate enough for personal and general business use, but they are not a substitute for legal, medical, or financial advice. For anything regulated, contractual notice periods, statutory deadlines, medical dating, double-check with the relevant authority.