CT600 corporation tax software for accountants

What it works out

• Profits chargeable, with disallowable expenses, entertaining and depreciation added back.
• Capital allowances: the annual investment allowance, full expensing, the 50% and 40% first-year allowances, zero-emission cars, and the main pool at 18% and then 14% from 1 April 2026.
• The 19% and 25% rates with marginal relief, divided for associated companies, split by financial year.
• Losses brought forward and carried forward.
• The date to pay and the date to file.

From the accounts to the return

The return starts from the accounts once they are approved, so the turnover, profit and depreciation come across without retyping. Dormant companies send the CT600 with the dormant reason.

Filing with HMRC switches on once HMRC has issued Accountin its own vendor ID. Until then the filing buttons are greyed out, and the return can still be prepared, printed and approved.