How Workdays Are Counted
A calendar has more days than a crew has workdays. The calculator walks the calendar one day at a time and keeps only the days your crew works.
1
Apply the Workweek
Days outside your workweek are skipped. On a Monday to Friday week, every Saturday and Sunday drops out.
2
Remove Holidays
Holidays on a workday are skipped. A Saturday holiday moves to Friday and a Sunday holiday to Monday, as federal rules do.
3
Subtract Weather Days
Planned weather days per month are spread across that month's workdays, so each day counts for slightly less than a full day.
4
Add the Cure Wait
A curing or inspection wait is added in calendar days after the last workday, then moved to the next workday if needed.
Federal Holidays and When They Are Observed
These are the 11 federal holidays under 5 U.S.C. 6103. Use them as a starting point, then adjust for your contract or union agreement.
| Holiday |
2026 Observed |
2027 Observed |
Rule |
| New Year's Day | Thu, Jan 1 | Fri, Jan 1 | Fixed date, Jan 1 |
| Martin Luther King Jr. Day | Mon, Jan 19 | Mon, Jan 18 | Third Monday in January |
| Washington's Birthday | Mon, Feb 16 | Mon, Feb 15 | Third Monday in February |
| Memorial Day | Mon, May 25 | Mon, May 31 | Last Monday in May |
| Juneteenth | Fri, Jun 19 | Fri, Jun 18 | Fixed date, Jun 19 |
| Independence Day | Fri, Jul 3 | Mon, Jul 5 | Fixed date, Jul 4 |
| Labor Day | Mon, Sep 7 | Mon, Sep 6 | First Monday in September |
| Columbus Day | Mon, Oct 12 | Mon, Oct 11 | Second Monday in October |
| Veterans Day | Wed, Nov 11 | Thu, Nov 11 | Fixed date, Nov 11 |
| Thanksgiving Day | Thu, Nov 26 | Thu, Nov 25 | Fourth Thursday in November |
| Christmas Day | Fri, Dec 25 | Fri, Dec 24 | Fixed date, Dec 25 |
2026 dates are from the OPM federal holiday schedule. 2027 dates are calculated here from the same rules. Saturday holidays are observed the Friday before and Sunday holidays the Monday after.
July 4, 2026 falls on a Saturday, so the observed day is Friday, July 3. Crews that follow federal observance lose a Friday, not a weekend day.
Why Construction Schedules Need Their Own Day Count
A generic business-day counter assumes everyone works Monday to Friday and takes every public holiday. Construction crews often do neither.
Some crews work six days or four ten-hour days. Many private jobs observe only a handful of holidays, and weather can stop outdoor work on days that are otherwise open.
Workdays also differ from elapsed time. Concrete cures every calendar day, so a curing wait belongs on the calendar, not in the workday count.
For a whole-project timeline, pair this tool with the project duration calculator and the construction schedule calculator.
For a single pour, the concrete pour duration calculator plans the hours inside one day, while this one plans the days around it.
Schedule Scenarios With the Dates Worked Out
These sample calculations show how holidays, a six-day week, and weather days change a date. They are illustrations, not documented projects.
🏗️ 30 Workdays Over Two Holidays
Start: Monday, November 2, 2026
Duration: 30 workdays, Mon to Fri
Holidays: all 11 federal
No holidays: finish Friday, December 11
Skipped: Wed Nov 11 and Thu Nov 26
With holidays: finish Tuesday, December 15
Calendar days: 44 including the start
With 2 weather days per month: Monday, December 21
Two holidays moved the date by two workdays. Weather days moved it by six more calendar days.
🔨 20 Workdays on a Six-Day Week
Start: Tuesday, September 1, 2026
Duration: 20 workdays, Mon to Sat
Holidays: six major
No holidays: finish Wednesday, September 23
Skipped: Mon Sep 7 (Labor Day)
With holidays: finish Thursday, September 24
A Saturday crew gets through 20 workdays in under four calendar weeks, and one holiday adds one day.
📆 Summer Window, Counted
Window: June 1 to August 31, 2026
Workweek: Mon to Fri
Holidays: six major, 3 weather days per month
Calendar days: 92
Weekend days: 26, leaving 66 weekdays
Holiday: Fri Jul 3 observed, leaving 65 workdays
Weather: 3 × 3 months = 9 days
Net workdays: 56 (19 in June, 19 in July, 18 in August)
Without the holiday or weather days, the same window would show 66 workdays. The difference is 10 days of schedule.
Holidays, Weather Days, and Contract Terms
🏛️
Holidays Are Your Call
Federal holiday law governs federal employees. Private crews follow the contract, union agreement, or company policy, so confirm which days are off.
🌧️
Weather Days
Contracts set either a designated number of weather days or a procedure to count them. Sample methods use 5 to 10 years of local weather records.
🌡️
Temperature Limits
Hot and cold weather can stop a pour even on a dry day. Check the concrete temperature limits before locking a pour date.
To turn workdays into labor cost, use the construction labor cost calculator with a rate from the construction labor burden calculator.
Quoting a job with dates? Use the construction quote builder, and see the guide to pouring a concrete slab for the order of work.
Sources and Method
- U.S. Office of Personnel Management, Federal Holidays (2026 schedule; 5 U.S.C. 6103, including the Saturday-to-Friday observance rule): opm.gov
- timeanddate.com, Business Days Calculator help (counting days between dates while excluding weekends or public holidays): timeanddate.com
- Omni Calculator, Working Days Calculator (weekend options and up to 50 custom holidays): omnicalculator.com
- Alabama Community College System, Calculation of Weather Days for Construction Projects (precipitation above 0.1 inch compared with a five-year average; notice within 21 days): accs.edu
- VERTEX, Incorporating Weather in Construction Schedules (contracts specify designated weather days or a procedure): vertexeng.com
- Cordulus, weather clause example (average monthly weather impact days over 10 years): cordulus.com
- NOAA National Centers for Environmental Information, historical weather records: ncei.noaa.gov
The calculator walks the calendar day by day. Weekend days and holidays on workdays are skipped. Weather days per month are spread evenly across that month's remaining workdays, so each day counts for 1 minus (weather days ÷ workdays in that month). Holidays for 2027 and later are calculated from the same rules as the 2026 schedule.
Last reviewed: November 2026. Reviewed by site author.
⚠️ Disclaimer
This calculator provides estimates for planning purposes. For permitted structural work, foundations, multi-story construction, retaining walls over 4 feet, and commercial projects, calculations must be verified by a licensed structural engineer per IBC 2024 §1604. ConcreteCalculate.com is not liable for structural decisions made from these estimates.
Contract dates, liquidated damages, and weather-day claims depend on your contract terms. Confirm them with your contract documents and an attorney or contract manager before relying on a date.
Calculations run entirely in your browser. No project data is stored or transmitted to any server beyond the calculation request itself.
