Business Days Calculator - Calculate Business Days Between Dates
Calculate business days (weekdays) between two dates. Excludes weekends automatically. Essential for project planning, delivery estimates, and business scheduling.
Reviewed by the Calcura editorial team · Last reviewed
- Question
- How do I count business days between two dates?
- Answer
- Count all days between the two dates, then subtract Saturdays and Sundays. For a full week (7 days), 5 are business days. Over longer spans, total_days × (5/7) is a good approximation, then adjust by the partial week at each end. For strict accuracy — especially legal deadlines — iterate day by day. Subtract listed holidays that fall on a weekday.
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- Formula
business_days = total_days − weekends − holidays- Caveats
- Western Mon–Fri workweek; some regions use Sun–Thu — check local convention.
- Shipping 'business days' excludes federal holidays; 'calendar days' in a contract does not.
- Court filing deadlines often extend to the next business day when they fall on a weekend.
What This Calculator Does
This calculator counts business days between two dates by iterating day-by-day and skipping Saturdays and Sundays. It does not skip public holidays — for that, subtract the holiday count manually or use a holiday-aware tool. Business days are the basis for shipping promises ('5–7 business days'), legal response windows (many court rules), banking settlement (ACH, wire same-day cutoffs), and SLA response times. The tool uses the Western Monday–Friday convention; some regions (e.g., Middle East) historically used Sunday–Thursday — adjust manually for those.
When To Use This Calculator
Checking shipping or fulfillment promises
A carrier quotes '5–7 business days' for a 2026-04-20 (Monday) ship date. Counting forward 5 business days lands on 2026-04-27 and 7 lands on 2026-04-29 — your realistic delivery window.
Responding within an SLA window
A customer-support SLA of '2 business days' for a ticket filed Friday afternoon means a response is due by end of Tuesday, not Sunday. Counting business days reveals the actual deadline.
Calculating bank-settlement or payroll cutoffs
A same-day ACH sent by 2:45 p.m. ET on a business day settles that day; after the cutoff or on a weekend, settlement is the next business day. Counting business days helps align employee pay dates.
Project planning with weekend-aware estimates
A 40-business-day project is 8 weeks of weekdays. Estimating 'roughly 2 months' is fine for narrative, but for a Gantt chart, the exact business-day count gives the date math.
How It Works
The tool walks from start to end one day at a time, incrementing the business-day count when the weekday is Mon–Fri (JavaScript getDay() 1–5) and the weekend count when it's Sat or Sun (0 or 6). Total days is the calendar difference plus one (inclusive on both endpoints). This method is correct for any span; more sophisticated approaches compute full weeks × 5 plus a partial-week remainder without iteration, but the results match. Holidays are not subtracted — treat the result as an upper bound when holiday days fall in the range.
Formula
For each date D from start to end inclusive:
if D.weekday ∈ {Mon..Fri}: businessDays += 1
else: weekends += 1
totalDays = (end − start in days) + 1Real-World Example
Scenario
A lawyer needs to file a response within 20 business days of service (a 2026-04-20 Monday service date) and wants the filing deadline.
Calculation
Starting Monday 2026-04-20, count 20 business days forward: Week 1 (4/20–4/24): 5 business days, count = 5 Week 2 (4/27–5/1): 5 business days, count = 10 Week 3 (5/4–5/8): 5 business days, count = 15 Week 4 (5/11–5/15): 5 business days, count = 20 Calendar span: 20 business days = 28 calendar days (no holidays skipped)
Result
The deadline lands on Friday, 2026-05-15. If any federal holidays fall in that window (e.g., Memorial Day is 2026-05-25, outside this range), add one more business day per holiday. Always confirm the court's local rules on how holidays are counted.
Common Mistakes to Avoid
Mistake: Forgetting holidays
Solution: '5 business days from Monday' including Memorial Day means 6 calendar business days actually elapse, but this calculator counts 5 weekdays regardless. For time-sensitive deadlines, check a holiday calendar and adjust.
Mistake: Mixing inclusive and exclusive counts
Solution: Some legal deadlines exclude the triggering day ('10 business days after service'), while shipping often includes the ship day. Check whether day zero is included — this calculator includes both endpoints by default.
Mistake: Assuming five-day weeks everywhere
Solution: Islamic-calendar countries (Saudi Arabia, UAE until 2022) used Sunday–Thursday workweeks. Israel uses Sunday–Thursday with a half-day Friday. For cross-border SLAs, confirm the counterparty's workweek.
Mistake: Overlooking timezone edge cases
Solution: A ticket filed at 11:45 p.m. ET Friday is still 'Friday' in ET but 'Saturday' in UTC — the calculator counts based on the date you input, not UTC. Use the relevant timezone's date.
Business Days vs. Related Calculators
Workdays Calculator
Similar counting logic; the workdays calculator may expose additional options (custom workweeks, holiday exclusion).
Date Difference Calculator
Counts total elapsed days without weekend exclusion — useful when the deadline is specified in calendar days instead.
Days Until Calculator
Counts down to a single future date in calendar days; use when the target date is known and you want a simple countdown.
When This Isn't the Right Tool
Legal deadlines governed by a specific rule set
Use instead: Federal Rules of Civil Procedure Rule 6 and state equivalents specify exactly how to count days (including holidays, half-day Saturdays in some contexts). For binding legal deadlines, cross-check with the applicable rule or counsel.
Banking settlement with Fed or ACH holidays
Use instead: Federal Reserve holidays and ACH calendar are authoritative for bank-day settlement. Consult the Fed's holiday schedule or NACHA rules rather than relying on weekend-only exclusion.
International shipping with country-specific holidays
Use instead: Cross-border shipments may skip both origin and destination holidays. Check the carrier's service-day calendar for the origin/destination pair.
Non-Monday-Friday workweeks
Use instead: For regions or businesses using Sunday–Thursday or alternative schedules, adjust the count manually; this calculator assumes Monday–Friday.
How to Verify This Calculation
In Excel, =NETWORKDAYS(start, end) returns business days between dates (inclusive, Monday–Friday). =NETWORKDAYS(start, end, holidays) subtracts a holiday list. Agreement confirms the result.
Sources
- Federal Reserve — Holiday Schedule — Official Fed bank-holiday calendar — used to distinguish Federal Reserve business days from calendar days.
- NACHA — ACH Operating Calendar — National Automated Clearing House Association: authoritative source for which days count as ACH business days.
- Federal Rules of Civil Procedure — Rule 6: Computing Time — US federal court rules on how to compute deadlines: includes explicit guidance on weekends and legal holidays.
Reviewed by the Calcura editorial team · Last reviewed