What are writing down allowances?
Writing down allowances spread equipment tax relief over time. The main-pool rate is generally 14% from April 2026 and the special-rate rate is 6%, applied to the remaining tax balance rather than the original purchase cost.
These answers provide general information, not advice tailored to your circumstances. Rules can change and exceptions may apply — speak to the CASS team before making a tax, accounting or financial decision.
Relief over several periods
Writing down allowances give tax relief on qualifying expenditure that remains after other allowances, or where upfront relief is unavailable. Assets are normally grouped into pools. The main-pool rate changed from 18% to 14% on 1 April 2026 for Corporation Tax and 6 April 2026 for Income Tax. An accounting period spanning the change uses a blended rate. The special-rate pool remains at 6%. These percentages apply to the remaining tax balance, so the deduction usually reduces over time. Different period lengths and private use can affect the calculation. CASS can classify the assets correctly and calculate the allowance available for the relevant period.
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