In The Business Plan Shop the financial years are necessarily 12 months long.
If you start trading during the year, the software will establish your financial statements over 12 months from the date of beginning of your business plan (for example from September to August).
The best practice in business planning is to always make financial forecasts for a full 12 months. Otherwise the financial years are not comparable and it is not possible to perform a financial analysis of the company.
However, if you wish to use the calendar year end as your financial or fiscal year end, you can do so as follows:
Choose January as the start month of the plan
Enter the first year's data in monthly, starting with the fiscal year start month
Note that if you choose this approach: you will not be able to use the sources and uses table.