Bas automatically invoices your storage per chosen period. The software always aligns these periods with the calendar: a full calendar month, a full calendar quarter or a full calendar year. If storage starts partway through such a period, that first part is calculated pro rata based on the number of days. Full periods follow after that.
So the system doesn't simply invoice 3 months ahead from the start date, but follows the calendar boundaries neatly.
Two settings determine the rhythm
1. The billing period - per day, week, month, quarter or year. You set this per storage case file.
2. Invoicing in advance or in arrears - does the customer receive the invoice at the start of the period (in advance) or after it ends (in arrears). For storage, invoicing in advance is most common. You can set this globally, or per case file.
Note: the from/to periods below are the same in both cases. Invoicing in advance or in arrears only determines when the invoice is prepared, not which period is shown on it.
Example: storage starts on 1 May
Per month
Period | Calculation |
1 May to 31 May | Full month |
1 June to 30 June | Full month |
and so on |
Per quarter
The quarters are: Jan-Mar, Apr-Jun, Jul-Sep and Oct-Dec.
Period | Calculation |
1 May to 30 June | Remainder of Q2, pro rata |
1 July to 30 September | Full quarter |
1 October to 31 December | Full quarter |
So invoicing doesn't simply run for 3 months from 1 May. The first part runs until the next quarter boundary (30 June), after which full quarters follow.
Per year
Period | Calculation |
1 May to 31 December 2026 | Remainder of the calendar year, pro rata |
1 January to 31 December 2027 | Full year |
Starting partway through a period?
Then you're only charged for the days that storage actually ran. “Pro rata” means: the number of days storage ran within that period, divided by the total number of days in that period.
Example: if storage starts on 12 May with monthly billing, the first invoice runs from 12 to 31 May. That's 20 of the 31 days, so you pay 20/31 of the monthly price. The following month (June) you're charged the full monthly price again.
If storage stops halfway through a period, the final part is settled pro rata in exactly the same way (via a credit note when the goods are removed).
Good to know
The period is always shown literally on the invoice line: “Storage ... for period 01-05-2026 to 30-06-2026”.
You set the billing period (day/week/month/quarter/year) per storage case file.
Invoicing in advance or in arrears doesn't change the from/to periods, only the invoicing moment.
The first and last part of a storage period are always calculated pro rata.