All calculators
Twelve focused, clutter-free date and time calculators. Pick the one that matches your question, every tool runs instantly in your browser.
What date and time calculators does Calcadian offer?
Calcadian offers twelve free date and time calculators: date difference, add or subtract days, business days, age, time duration, weekly time card, ISO week number, day of the week, days until, Unix timestamp converter, weeks between dates, and time since. Each tool runs in your browser, requires no sign-up, and works on mobile and desktop.
Browse all date and time calculators
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.
Business Days Calculator
Count working days between two dates, excluding weekends.
Age Calculator
Calculate exact age from any date of birth.
Time Duration Calculator
Calculate hours and minutes between two times.
Weekly Time Card Calculator
Add up a full week of shifts with breaks and overtime.
Week Number Calculator
Find the ISO week number for any date.
Days Until Calculator
Count how many days are left until any future date.
Time Since Calculator
See how long ago a past date was, in years, months, and days.
Weeks Between Dates Calculator
Calculate total weeks, remaining days, and decimal weeks between two dates.
Day of the Week Calculator
Find what day of the week any date falls on.
Unix Timestamp Converter
Convert between Unix epoch time and readable dates.
Two categories, one toolkit
Calcadian's tools split into two groups. Date calculators work in whole-day terms, counting days between dates, projecting a date forward or back, working out an age, or finding an ISO week. Time calculators handle smaller units: hours and minutes between two times, or converting between Unix timestamps and readable dates. Pick the category that matches the precision you need.
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 |
| Business Days | You only want to count working days. | Workday count, excluding weekends + custom holidays |
| Age | You need an exact age from a date of birth. | Years, months, days |
| Time Duration | You're measuring hours and minutes inside a day. | Hours and minutes, with optional breaks |
| Weekly Time Card | You're adding up a whole week of shifts for payroll. | Daily and weekly hours, decimal hours, overtime, estimated pay |
| Week Number | You need the ISO week for a date. | Week number, week year, week range |
| Day of the Week | You need the weekday for a past or future date. | Weekday, day of year, ISO week |
| Days Until | You're counting down to a fixed future date. | Days remaining (or elapsed) |
| Unix Timestamp | You're working with epoch seconds or developer logs. | Local + UTC date, or a Unix timestamp |
| Weeks Between Dates | You want to know how many weeks span two dates. | Whole weeks plus remaining days, decimal weeks, total days |
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.