This article is information on how you would record an accounting period of over 12 months.
There are DIY Accounting Limited Company packages for each month end.
For the first year many companies have more than a 12 month accounting period.
Depending on how much over 12 months the first year is and whether trading started right away you may need to file 2 returns to HMRC and 1 to Companies House.
The easiest thing to do would to inform HMRC you didn't start trading right away and have a 12 month return.
Which ever way it is, you'll need to start will all your transactions in the same place to have a full view of the first period.
Initially take the product that matches your year end and put the first transactions in the first month's sheet even if they actually fell in an earlier month.
Companies House will probably want a return for the whole period whereas HMRC will want one return of a maximum of 12 months and another shorter one.
When you find out how they want to split things up (notice to complete CT600 from HMRC) you can check you’ve still got a package with the right year end for the larger period in the split then carry on.
When you come to file use HMRC’s online filing PDF (which also submits to Companies House for you) download a copy for the date range covering everything Companies House want, complete the form fully to run your figures through the validation rules but don’t submit yet.
Next the painful first year only bit... You’ll need to split your accounts into two sets one for the earlier period and one for the later.
Do this by making two copies of the full set and zero/blank out the overlapping transactions (zero/blank out don't delete rows).
You'll need to take the closing figures from the first set and enter these in "Open Accounts" for the second set.
When that’s done check the year end figures in the split set match the end figures in the full set your are ready to file: The full period to Companies House Both short periods to HMRC