Capex vs Opex for AI Infrastructure – UK Perspective

For UK businesses, the capex-vs-opex decision on AI infrastructure has specifically British tax and accounting implications. Both paths have legitimate uses. On our UK dedicated hosting opex is the straightforward choice, but here is when capex makes sense.

Contents

• Annual Investment Allowance
• R&D tax relief
• Cashflow
• Decision framework

AIA

UK Annual Investment Allowance in 2026 is £1M per year. Capital spend on plant and machinery (including GPU hardware) below this threshold can be deducted in full against profits in the year of purchase.

A £30,000 GPU server purchased outright could fully reduce tax at the corporate rate (25% for most companies) – an instant £7,500 tax benefit versus amortising over years.

R&D Relief

If you qualify for UK R&D tax relief (SME scheme or RDEC), qualifying R&D expenditure – which can include certain AI infrastructure costs – benefits from enhanced deductions or credits.

Opex hosting can qualify as R&D expenditure for the proportion used in genuine R&D activity. Capex can qualify too, through the R&D capital allowances route. Consult an R&D tax specialist – the rules are specific.

Cashflow

Opex is smooth – £500/month is £500/month. Capex is lumpy – £30,000 today, then zero direct cost for years.

For bootstrapped businesses, opex typically wins. For well-funded businesses with strong current-year profit, capex plus AIA can be tax-efficient.

Framework

See depreciation accounting.