Free business calculator
Weekly Seasonality Index Calculator
Find which spots in a repeating week run above or below normal.
- Instant results
- Private in your browser
- PDF report included
Use the result well
A clear answer, with the assumptions visible
These recommendations turn the result into an operational next step without hiding the inputs behind a score.
- 1
Start every week on the same named day.
- 2
Use more weeks before treating a small gap as a pattern.
- 3
Mark holidays, closures, and promotions beside the result.
How this tool works
- Keep only complete seven-value weeks.
- Use simple-statistics to average each weekday and the full set.
- Divide each weekday average by the overall average to create a seasonality index.
Build it in Bookify
Set up scheduling Use the pattern in your schedule
Keep staff, clients, and bookings together in Bookify.