Plain-English guides to UK Corporation Tax and CT600 filing.
Miss your CT600 deadline and HMRC charges escalating penalties — from £200 on day one for filing dates from April 2026, rising to 10% of unpaid tax. Learn the full penalty structure, appeal options, and how to file on time.
HMRC withdrew its free CT600 filing service on 31 March 2026. Learn what this means for your company, your options for filing going forward, and how to switch to affordable software.
Complete guide to HMRC Business Tax Account for limited companies. Learn how to register, access your corporation tax records, check deadlines, view payments, and manage your CT600 obligations online.
Sage Accounting does not file CT600 returns to HMRC. Learn what Sage does for corporation tax, its limitations, and how to pair it with Taxpipe for affordable CT600 filing.
Need to file a CT600 for a period shorter than 12 months? Learn when short periods happen, how tax is calculated, financial year splits, and how to avoid HMRC rejection errors.
Complete guide to micro-entity accounts for UK limited companies. Learn the qualifying thresholds, what to include, FRS 105 requirements, and how they work with your CT600 filing.
QuickBooks does not file CT600 returns to HMRC. Learn what QuickBooks does for corporation tax, its limitations, and how to pair it with Taxpipe for affordable CT600 filing.
FreeAgent can file CT600 returns for most micro-entities directly with HMRC. Learn what FreeAgent covers, where it falls short, and when Taxpipe is a better fit for your CT600 filing.
Complete guide to corporation tax loss relief. Learn how to carry forward trading losses, carry back to previous years, claim group relief, and which CT600 boxes to use for each type of relief.
Complete guide to claiming R&D tax credits on your CT600. Covers the merged R&D scheme, qualifying expenditure, CT600L supplementary page, HMRC compliance checks, and cash credits vs tax reduction.
Complete guide to claiming capital allowances on your CT600. Covers Annual Investment Allowance (AIA), writing down allowances, first-year allowances, full expensing, and which CT600 boxes to fill in.
Made an error on your CT600? Learn exactly how to amend your corporation tax return, HMRC time limits, penalties for mistakes, and how to fix common CT600 errors step by step.