THE NUMBERS, EXPLAINED
How to use this calculator.
The start date is not counted. Saturday, Sunday and supplied holidays are skipped. Zero days returns the start date.
Start with your inputs
Enter start date, working days to add, holidays, comma-separated or none. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Start date | 2026-01-09 |
| Working days to add | 1 |
| Holidays, comma-separated or none | none |
A worked example
With the example inputs above, deadline is 2026-01-12. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Deadline | 2026-01-12 |
How this is calculated
Deadline
addWorkingDays(a,b,c)
Symbols and units
- a
- Start date
- b
- Working days to add
- c
- Holidays, comma-separated or none
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Calculation steps and notation
Start after the entered date and advance one calendar day at a time. Count only Monday–Friday dates that are not in the supplied holiday list. Zero additional days returns the starting date.
Assumptions and limits
The start date is not counted. Saturday, Sunday and supplied holidays are skipped. Zero days returns the start date.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Deadline. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: The start date is not counted. Saturday, Sunday and supplied holidays are skipped. Zero days returns the start date.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →