How Many Days Between Two Dates? How to Count Days, Weeks and Workdays

By Abdur RehmanNovember 1, 20263 min read🖨 Print

Quick answer: subtract the earlier date from the later one. From March 15 to August 1, 2026 is 139 days — 19 weeks and 6 days, or 4 months and 17 days. Add 1 if you want to count both the start and end date. Enter any two dates below to get days, weeks, months and business days.

Counting days sounds simple until months of different lengths, leap years and weekends get involved. Whether you're counting down to a trip, working out a notice period, tracking a pregnancy or checking a deadline, here's how to get the right number every time.

How to count days between dates by hand

Example: March 15 to August 1, 2026.

1. Days left in the first month: March has 31 days, so 31 − 15 = 16 days.
2. Full months in between: April (30) + May (31) + June (30) + July (31) = 122 days.
3. Days in the last month: 1 (up to August 1).
4. Total: 16 + 122 + 1 = 139 days.

Days in each month

The old rhyme helps: "Thirty days hath September, April, June and November." Leap years — when February has 29 days — happen in years divisible by 4, except century years not divisible by 400. 2028 is the next leap year; 2100 won't be one.

Should you include the end date?

This is where most counting mistakes happen.

• Difference between dates (default): Monday to Friday = 4 days. This is what you want for "how many days until…", ages and countdowns.
• Counting both dates (inclusive): Monday to Friday = 5 days. Use this for event days, leave you're taking, or a contract "from 1 March to 31 March inclusive" (31 days).

Tick Include end date in the calculator to add the extra day.

How to count business days

For deadlines, delivery estimates and notice periods you often need working days only. From March 15 to August 1, 2026 there are 100 weekdays (Monday–Friday). The calculator shows business days automatically, and you can change the weekend to Friday–Saturday, Friday only or Sunday only for countries with a different working week.

Public holidays aren't removed automatically, because they differ by country and region — subtract any that fall in your range.

Counting days in Excel and Google Sheets

• =B1-A1 — days between two dates (format the cell as a number, not a date).
• =B1-A1+1 — counting both dates.
• =DATEDIF(A1,B1,"d"), "m" or "y" — complete days, months or years between them.
• =NETWORKDAYS(A1,B1) — working days Monday–Friday, including both dates. Add a range of holiday dates as a third argument to skip them.
• =NETWORKDAYS.INTL(A1,B1,7) — working days with a Friday–Saturday weekend.
• =TODAY()-A1 — days since a date.

Common questions people count

• Days until a date: put today as the start date and the event as the end date — the calculator also shows the gap in weeks and in years, months and days.
• A date X days from now: "What's the date 90 days from today?" is the opposite question — use the date calculator to add or subtract days, weeks, months or years.
• Your age in days: the age calculator gives your exact age in years, months and days, and your total days alive.
• Weeks between dates: divide the days by 7 — the calculator shows weeks and remaining days.
• Working hours across those days: see how to calculate hours worked.

Why months and years can be tricky

"One month" isn't a fixed number of days. January 31 plus one month has no exact answer, because February has no 31st — most systems, including the date calculator here, land on the last day of February. That's why contracts and visa rules often state periods in days (such as "90 days") rather than months: days are unambiguous.

Frequently asked questions

Written by Abdur Rehman

ERP developer and AI & automation engineer who builds and maintains every tool on WebToolNest. More about me.