Write the actual pattern first
A daily average is a convenient input, not a description of every household. If you prepare two coffees on five days and one on two days, the week contains twelve preparations. Dividing by seven gives an average you can use for an approximate longer-period calculation.
If the dose also changes, one average drink count is not enough. Calculate the coffee mass for each preparation type separately and add those totals. Keep the assumptions visible so the result can be checked.
Choose a period you can explain
A seven-day plan is different from a calendar month. The tool asks for the number of days, so you can enter the period you mean rather than relying on a hidden thirty-day convention. Time away or an unusual week may warrant a separate scenario.
For a deliberately finite batch, set daily preparations and days so their product equals your planned number of preparations. Label the saved record clearly. The calculator does not inspect your calendar or infer guests, workdays or holidays.
Compare predictions with actual stock
At the end of the period, note the coffee remaining and any unplanned use you know about. Do not automatically interpret a difference as grinder waste: changed recipes, additional preparations and uncertain starting stock can all affect the comparison.
Our optional extra percentage is an explicit planning assumption, not a measured loss rate. Use zero unless you have a reason for an allowance, and revisit it when you have better information. The purpose is to make the next estimate easier to explain, not to prescribe how much coffee anyone should drink.
Worked examples and organizational methods are our planning analysis, not product tests. Follow complete model instructions. No electrical, heat, steam or installation assessment is provided. Our research method.