📅 Date Calculator
Calculate days between dates, add or subtract days, find business days, and plan events with precision.
Calculate days between dates, add or subtract days, find business days, and plan events with precision.
Our date calculator helps you work with dates for planning events, calculating deadlines, tracking project timelines, and more.
Calendar days include all days (weekdays + weekends). Business days typically exclude Saturdays and Sundays. For legal or financial deadlines, always clarify which type of days are meant.
| Holiday / Event | Date (2026) | Day |
|---|---|---|
| New Year's Day | January 1 | Thursday |
| Valentine's Day | February 14 | Saturday |
| Easter Sunday | April 5 | Sunday |
| Memorial Day (US) | May 25 | Monday |
| Independence Day (US) | July 4 | Saturday |
| Labor Day (US) | September 7 | Monday |
| Thanksgiving (US) | November 26 | Thursday |
| Christmas Day | December 25 | Friday |
Remember with this rhyme: "30 days has September, April, June, and November. All the rest have 31, except February which has 28 (or 29 in leap years)."
A year is a leap year if:
ISO week numbering: Week 1 is the week containing the first Thursday of the year. A year has 52 or 53 weeks.
Quick reference data for common date calculations, business day counts, and time unit conversions:
| Month | Days (regular) | Days (leap year) | Quarter | Business Days (avg) |
|---|---|---|---|---|
| January | 31 | 31 | Q1 | 23 |
| February | 28 | 29 | 20 | |
| March | 31 | 31 | 23 | |
| April | 30 | 30 | 22 | |
| May | 31 | 31 | 22 | |
| June | 30 | 30 | 21 | |
| July | 31 | 31 | 23 | |
| August | 31 | 31 | 22 | |
| September | 30 | 30 | 22 | |
| October | 31 | 31 | 23 | |
| November | 30 | 30 | 20 | |
| December | 31 | 31 | 22 | |
| Full Year | 365 | 366 | × | ~261 |
Find the number of days between two dates, or add days to a date.
Counting the days from New Year's Day to year-end.
Result: = 364 days (365 in a leap year).
Adding a 90-day deadline to a start date.
Result: Useful for contracts, returns and notice periods — the tool counts calendar days.
Excluding weekends from a span.
Result: Two weeks = 14 calendar days but only 10 business days.
Subtract the earlier date from the later one — the calculator handles months and leap years.
Exclude weekends (and holidays) — two weeks is 14 calendar but 10 business days.
Enter a start date and number of days; the tool returns the resulting calendar date.