All calculators
Nine 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 nine free date and time calculators: date difference, add or subtract days, business days, age, time duration, ISO week number, days until, Unix timestamp converter, and weeks between dates. Each tool runs in your browser, requires no sign-up, and works on mobile and desktop.
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.
Week Number Calculator
Find the ISO week number for any date.
Days Until Calculator
Count how many days are left until any future date.
Weeks Between Dates Calculator
Calculate total weeks, remaining days, and decimal weeks between two dates.
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 |
| Week Number | You need the ISO week for a date. | Week number, week year, week range |
| 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.