company_chargeable_gain_with_indexation
ClaudeWorks out a UK limited company's chargeable gain or allowable loss when it sells UK land or buildings, or shares it bought in one purchase, including indexation allowance frozen at December 2017. It shows the Retail Prices Index figures and factor used, and applies the rule that indexation can't create or increase a loss.
corporation_tax_deadlines
ClaudeWorks out a UK private limited company's Corporation Tax payment date, CT600 filing deadline and Companies House accounts deadline from its accounting period. Accounts longer than 12 months are split into two Corporation Tax periods, each with its own payment date.
corporation_tax_late_penalty_and_interest
ClaudeWorks out HMRC's penalties for filing a UK company's Company Tax Return (CT600) late — the flat £200/£400 penalties for filing deadlines from 1 April 2026 (£100/£200 before then), and the 10% or 20% tax-geared penalty — plus late payment interest on the Corporation Tax at HMRC's published rates.
directors_loan_s455_tax
ClaudeWorks out the section 455 tax a UK close company owes on a director's or shareholder's loan still owed at the end of its accounting period, the relief for any part repaid within 9 months, the net tax and its due date. Uses the rate for the date the loan was made, including 35.75% from 6 April 2026.
long_accounting_period_split
ClaudeSplits UK company accounts covering more than 12 months (up to 18) into the two Corporation Tax accounting periods, with each period's dates, days, payment deadline and share of the profit by days, plus the CT600 filing deadline for both returns and the Companies House accounts deadline.
uk_company_capital_allowances
ClaudeWorks out a UK limited company's capital allowances for one accounting period: the annual investment allowance, full expensing, the 50% and zero-emission car first-year allowances, and writing-down allowances at 14% (18% before 1 April 2026, a hybrid rate for a period spanning that date) and 6%. It also shows balancing charges and the pools carried forward.
uk_company_size_micro_small_check
ClaudeChecks whether a UK private company is a micro-entity, small, or neither for a financial year under the Companies Act 2006, using the limits raised for years starting on or after 6 April 2025, the 2-of-3 test, turnover pro-rating for short or long years, and the two-consecutive-years rule.
uk_corporation_tax_estimate
ClaudeEstimates the Corporation Tax a UK limited company pays on its taxable profits for one accounting period of up to 12 months. Applies the small profits rate, the main rate and marginal relief, with associated companies, short periods and periods that straddle 1 April. A close investment-holding company pays the main rate on all its profits. Returns the tax, the effective rate and the payment and filing dates.
