The business days calculator answers the two questions behind every deadline that must not land on a weekend: how many working days lie between two dates, and what date falls N working days after (or before) a start date. Both modes exclude Saturdays and Sundays, and both let you add your own holidays — enter them as a simple list of dates (YYYY-MM-DD) that is stored only in your browser’s local storage. The count convention is stated on the page: business days are counted from the day after the start date through the end date, so a Monday-to-Friday week is 4 business days unless you enter the Friday as an explicit holiday. The add mode advances by calendar weekdays, skipping weekends and holidays, and supports negative counts for deadlines that precede a date. All calendar math is done with explicit day arithmetic — no floating-point dates, no time-zone ambiguity, because the calculator works with calendar dates only. Everything runs locally in your browser: dates and holiday lists never leave your device and are never logged. Use this calculator for delivery promises, approval timelines, and anything contractual that must count only working days.
How is the result calculated?
Delivery promise: 5 business days from Friday
An order placed on Friday, August 7, promises delivery in 5 business days. Saturday and Sunday do not count, so the 5th business day lands on Friday, August 14. If Monday were a public holiday, the promise would move to Monday, August 17 — which is why the holiday list matters for real deadlines.
Example input and output | Input | Value |
| startDate | 2026-08-07 |
| days | 5 |
| Result | 2026-08-14 (skipping the weekend) |
What is the formula and its assumptions?
Business days between dates
count = weekdays in (start, end], minus holidays
Formula terms | Symbol | Meaning |
(start, end] | the day after start through end, inclusive of end |
holidays | dates in the holiday list that fall on weekdays |
Add business days
date = start + N weekdays, skipping weekends and holidays
Formula terms | Symbol | Meaning |
N | whole number of business days (negative moves backward) |
What are the most common mistakes?
- Counting the start date as a working day — the count starts the day after.
- Forgetting holidays for the region where the work actually happens.
- Assuming "3 business days from Friday" means Wednesday — it means the following Wednesday, because the weekend does not count.
What are the assumptions and limitations?
- Holidays are the ones you enter — no built-in country calendars in version 1.
- The calculator works with calendar dates only; hour-level precision is out of scope.
- Conventions vary by contract; the method shown on the page is the one the calculator uses.
Where do the numbers come from?
Last reviewed August 4, 2026 · Version 1.0.0 · Toolivaro does not guarantee external content.
Frequently asked questions
Why is Monday-to-Friday only 4 business days?
Because the start day itself is not counted — the count runs from the day after the start through the end date. If your convention counts the start day, add one day to the result.
Where are my holidays stored?
Only in your browser’s local storage on your device. They are never transmitted anywhere, and they stay attached to this site only.
Can I count backward from a date?
Yes — the add mode accepts negative day counts and moves backward, skipping weekends and holidays in the opposite direction.
Part of Time, date, and scheduling tools
Found a mistake or have a correction? Report it — we review every correction.
Reviewed by the Toolivaro editorial team per our methodology Methodology · Editorial policy