Cash-flow period entry sheet

List one row per modeled interval

Start with period zero and record the length of each subsequent interval. The fictional sheet uses annual intervals, two zero periods and a receipt at time three. Keep those rows even when their cash flow is zero.

Combine only simultaneous flows

A row can contain the net amount of flows at the same modeled date. Do not move a receipt from a later date into the initial row just because the labels share a year. A calendar-date model with irregular intervals needs a separate timing method.

Identify consecutive repeated amounts

Keep the discount interval with the schedule

The example mathematical check uses 10% per annual interval and yields NPV 51.840721. The CSV itself performs no valuation. Changing periods or amounts requires recalculation, and changing the calendar unit requires a matching rate convention.