Business Day Date Calculator
Add or subtract working days with your weekend pattern and excluded dates. Find a completion date or work backward from a deadline.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Move one calendar day at a time in the selected direction. Count a day only if it is not a selected weekly day off and not in the entered excluded-date set. Stop after the requested working-day count.
Result date=start date shifted by N eligible working days; starting date is excluded
Worked example
From Monday 2026-10-26, adding 5 business days with Saturday/Sunday off gives Monday 2026-11-02. Excluding 2026-10-28 moves the result to Tuesday 2026-11-03.
Assumptions and input details
The starting date never counts as day one. A zero offset returns the unchanged starting date, even on a day off. Negative offsets count backward using the same rules; enter a deadline as the starting date to find an earlier date. Dates and results must be within 1900–2199; offsets are whole numbers from −10000 to 10000. Enter up to 2000 excluded dates; duplicates count once and overlaps with weekends are not counted twice. No country holidays are supplied automatically. Date-only UTC arithmetic avoids browser timezone and daylight-saving shifts. The table shows the first 100 visited dates plus the final date when longer.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Count calendar days between two Gregorian dates, optionally including both endpoints. View the direction, week breakdown and Monday–Friday versus weekend counts.
Add or subtract up to 100 durations. Use signed clock durations or decimal hours, minutes or seconds, then compare the exact total and running sums.
Calculate how long two constant-rate workers, machines or pipes take together. Include an opposing drain and an already-completed fraction, with a progress graph.
Reserved advertising space.