Count Days Between Two Dates
Enter two dates to see exactly how many days are between them.
How Days Between Dates Works
Four steps to count days between any two dates.
Enter From Date
Pick the start date — the beginning of the period you want to count.
Enter To Date
Pick the end date. Click "To = Today" for counting up to the current date.
Calculate
Click "Count Days" and the tool computes the exact difference in calendar and business days.
View Breakdown
See total days, business days, weekends, weeks, hours, and approximate months.
What Is a Days Between Dates Calculator?
Understanding day counting between dates.
Day counting explained
A Days Between Dates Calculator finds the exact number of calendar days between two dates. It subtracts the earlier date from the later date, accounting for month lengths, leap years, and year boundaries.
Unlike year/month/day breakdowns, this gives a single total day count — useful for comparisons, deadlines, and age-in-days calculations.
Business vs calendar days
Calendar days include every day. Business days skip weekends (Saturday and Sunday). A 30-calendar-day period contains about 21-22 business days. Legal deadlines, shipping estimates, and bank processing often use business days.
Inclusive vs exclusive counting
From January 1 to January 3: 2 days (exclusive — counting midnights). If you want both dates included, add 1 for 3 days (inclusive). Most applications use exclusive counting. Include hours and minutes as well with the date duration calculator.
When to Count Days Between Dates
Common day counting scenarios.
Shipping Tracking
Count transit days from ship date to expected delivery. Compare actual vs estimated delivery timeframes.
Medical Records
Track days since surgery, treatment start, or symptom onset. Doctors need exact day counts for medical records.
Legal Deadlines
Count statute of limitations days, filing deadlines, and response periods with precision.
Interest Calculations
Banks calculate daily interest based on exact day counts. Know the precise number of days for loan or savings calculations.
Academic Planning
Count days until graduation, exam dates, or semester breaks. Plan study schedules based on remaining days.
Fitness Goals
Track training streaks and days since starting a fitness program. Count days to goal completion.
Days Between Dates Examples
Common day count scenarios.
New Year to today
Jan 1 → Jun 23 = 173 days. Almost halfway through the year (47.4%).
Quarter length
Jan 1 → Mar 31 = 89 days (90 in leap year). A standard fiscal quarter.
Full year
Jan 1 → Dec 31 = 364 days. A year minus 1 day (inclusive counting gives 365).
Step-by-Step Walkthrough
Counting a real interval by hand, then splitting it into the working days that a plan actually runs on.
A contract runs from Monday 3 March 2025 to Friday 15 August 2025. How many days is that, and how many of them are working days?
Count the days remaining in the first month
March has 31 days 31 − 3 = 28 days remaining after 3 MarchCounting from the start date rather than from the 1st avoids an off-by-one at the very first step, which is where most manual date counts go wrong.
Running total28 days
Add the whole months in between
April 30 + May 31 + June 30 + July 31 = 122 daysEach month contributes its actual length. Using 30 across the board would give 120 and lose two days — enough to shift the weekday of the result.
Running total122 days
Add the days in the final month
28 + 122 + 15 = 165 daysAdding 15 counts up to and including 15 August. This is the exclusive count — the number of days you would advance a calendar, not the number of dates covered.
Running total165 days
Split out the weekends
165 ÷ 7 = 23 weeks remainder 4 23 × 2 = 46 weekend days 165 − 46 = 119, adjust for the 4 extra days → 118 business daysTwenty-three complete weeks contribute exactly two weekend days each. The remaining four days need checking against the actual calendar, since they may or may not include a weekend.
Running total≈ 118 business days
Express in other units
Weeks: 165 ÷ 7 = 23.57 Hours: 165 × 24 = 3,960 Months: 165 ÷ 30.44 ≈ 5.42Weeks and hours are exact. The month figure is an approximation — five and a half months is a description, not a date you can act on.
Running total23.57 weeks / 3,960 hours
3 March to 15 August 2025 is 165 days — 23.57 weeks, 3,960 hours, and roughly 118 business days once weekends come out.
Common Mistakes and Pro Tips
Mistakes that quietly corrupt your numbers
Assuming the count includes both the start and end dates.
Decide explicitly whether you want the interval (165) or the dates covered (166).
Why it matters: The two differ by exactly one, and both are legitimate answers to differently phrased questions. Hire periods, notice periods and hotel stays each use a different convention, so the ambiguity has real financial consequences.
Estimating with 30-day months to save time.
Count each month at its true length.
Why it matters: Over five months the approximation drifts by several days. Since business-day counts depend on the day total modulo seven, a two-day error can change the working-day figure by more than two.
Treating business days as though it accounted for public holidays.
Business days exclude weekends only — subtract holidays separately.
Why it matters: A five-month window in most countries contains several public holidays. Planning against 118 business days when 112 are actually available is a 5% over-commitment before any work has started.
Forgetting that leap years add a day to any interval spanning 29 February.
Check whether the interval crosses a leap day.
Why it matters: It is a single day, but it is a silent one. An interval calculated from a month-length table that assumes 28 days in February will be exactly one day short in a quarter of all years.
Pro tips
State your counting convention
Write "165 days, exclusive of the start date" rather than just "165 days". The off-by-one is the most common dispute in any date calculation, and one clause prevents it.
Plan in business days
Roughly five sevenths of any interval is working time. Converting early is what keeps a plan realistic rather than optimistic.
Subtract holidays yourself
No general day counter knows your country’s public holidays or your organisation’s closures. List them and take them off the business-day figure explicitly.
Use weeks for communication
"About 23 and a half weeks" lands better than "165 days" in a planning conversation, while the day count stays available for anything precise.
Check for a leap day
Any interval crossing 29 February gains a day. It is easy to miss and it is exactly the kind of single-day error that surfaces at a deadline.
Treat the month figure as a label
Months are averaged at 30.44 days here. Use them to describe the scale of an interval, never to derive a date.
Days Between Dates — Common Intervals
Reference intervals in days, weeks and approximate business days, with leap-year effects noted.
| Interval | Days | Weeks | ≈ Business days | Note |
|---|---|---|---|---|
| 1 week | 7 | 1.00 | 5 | |
| 2 weeks | 14 | 2.00 | 10 | |
| 30 days | 30 | 4.29 | 22 | |
| 1 month (Jan) | 31 | 4.43 | 23 | Longest months |
| 1 month (Feb) | 28 | 4.00 | 20 | 29 in leap years |
| 45 days | 45 | 6.43 | 32 | |
| 1 quarter | 91 | 13.00 | 65 | Exactly 13 weeks |
| 165 days | 165 | 23.57 | 118 | Mar 3 → Aug 15 |
| 180 days | 180 | 25.71 | 129 | |
| 6 months | 182 | 26.00 | 130 | Half of 364 |
| 1 common year | 365 | 52.14 | 261 | |
| 1 leap year | 366 | 52.29 | 262 | Includes 29 Feb |
| 2 years | 730 | 104.29 | 522 | Add 1 if leap |
No rows match that filter.
Business days exclude weekends but not public holidays. A quarter is exactly 13 weeks, which is why quarterly reporting periods align neatly to weekdays. For the same interval broken into years, months and days, use the date duration calculator.
Counting Days Correctly
Conventions, weekends and the calendar rules underneath.
Inclusive versus exclusive counting
Two reasonable answers exist for "how many days from 3 March to 15 August". The exclusive count is 165 — the number of midnights crossed, or how far you would advance a calendar. The inclusive count is 166 — the number of dates in the range.
Neither is more correct; they answer different questions. A notice period usually counts exclusively, while a hire period or a hotel stay usually counts the dates covered.
The failure mode is never stating which. This calculator returns the exclusive interval, which is the standard for date arithmetic — add one if you need dates covered.
Why business-day counts need care
A complete week always contains exactly five weekdays, so the bulk of any business-day count is simply whole weeks × 5. The difficulty is entirely in the remainder.
Four leftover days might contain zero, one or two weekend days depending on which weekday the interval starts on. That is why the remainder has to be checked against the actual calendar rather than scaled proportionally.
It also means two intervals of identical length can have different business-day counts — a fact that surprises people building schedules from day totals alone.
The working week is not universal
Monday to Friday is common but far from global. Several countries in the Middle East observe a Friday–Saturday or Friday-only weekend, and some organisations run six-day weeks.
A business-day count assuming a Saturday–Sunday weekend will be wrong for those contexts, and wrong in a way that compounds over long intervals.
For international projects, agree which days count as working days before agreeing the schedule. It is a larger source of misalignment than time zones.
How date arithmetic is done under the hood
Software rarely counts days by walking through months. Instead each date is converted to a single number — days since a fixed epoch — and the two numbers are subtracted.
That approach handles leap years, varying month lengths and century rules automatically, because they are all baked into the conversion rather than applied afterwards.
It is also why a computed day count is reliable while a hand count is not: there is only one place for the calendar logic to live, and it is the same code every time.
Frequently Asked Questions
Common questions about the Days Between Dates Calculator.
How do I count days between two dates?
Enter a start date and end date. The calculator instantly shows the total number of calendar days between them, plus business days, weekend days, and complete weeks.
Does it include the start and end dates?
By default the calculator counts the days between (exclusive). The result equals the number of midnights between the two dates. If you need inclusive counting, add 1 to the result.
What are business days?
Business days are weekdays — Monday through Friday. The calculator counts how many weekdays fall between the two dates. Public holidays are not excluded since they vary by country.
Can I count days between past and future dates?
Yes. Enter any two dates regardless of whether they are in the past or future. The calculator always returns the absolute number of days between them.
How accurate is the calculation?
The calculator uses the JavaScript Date API with full Gregorian calendar support. It correctly handles leap years, varying month lengths, and date boundary crossings for complete accuracy.
Is this days between dates calculator free?
Yes, completely free. No sign-up needed. All calculations happen in your browser — your data is never stored or transmitted.
Does the count include both the start and end dates?
No — it returns the exclusive interval, which is the number of days you would advance a calendar. From 3 March to 15 August that is 165 days. If you need the number of dates covered, including both endpoints, add one to give 166.
What counts as a business day?
Monday to Friday. Weekend days are excluded, but public holidays are not — no general day counter knows your country’s holiday calendar, so subtract those separately from the business-day figure.
Why is the month figure marked as approximate?
Because calendar months vary from 28 to 31 days, so the conversion uses an average of 30.44. It describes the scale of an interval accurately enough but should never be used to derive a specific date.
Does the calculator handle leap years?
Yes. Any interval spanning 29 February automatically includes that extra day, which is one reason a computed count is more reliable than one worked out from a table of month lengths.
Does the order of the two dates matter?
Not for the day count — the interval between two dates is the same either way. The calculator reports the magnitude of the gap regardless of which date you enter first.