How Does Taking a Business Loan Affect Your Company's Corporation Tax Bill?

Borrowing the principal is not taxable income

When your company receives loan proceeds, those funds are not treated as taxable income. A loan creates a liability on the balance sheet — the company owes the principal back — so there is no net increase in wealth that could be taxed. Equally, repaying the principal is not a deductible expense; it is simply a reduction of the liability. Only the financing cost (interest and qualifying fees) affects your tax position.

Interest reduces taxable profits year by year

Each year that your company pays interest on a loan, that interest is deducted from profits before corporation tax is calculated. For a company at the 25% main rate, every £1 of deductible interest saves £0.25 in tax. Over a five-year term loan with £50,000 of total interest, the cumulative tax saving would be £12,500 at the main rate — though the annual benefit depends on the interest schedule and the company's actual tax position in each year.

These figures are illustrative and not a quote or advice. Your accountant will model the actual tax impact based on your company's specific projected profits, the applicable rate, and the loan terms.

What the loan funds buys matters

The use of the loan proceeds determines what additional tax reliefs, if any, are available beyond the interest deduction. If the funds are used to:

• Buy plant, machinery, or equipment — capital allowances (AIA or writing-down) give additional relief on the asset cost.
• Fund day-to-day working capital — expenditure already deducted in the P&L (wages, materials, overheads) gives its own revenue deduction; the loan interest is on top.
• Acquire property — different rules apply; capital allowances on fixtures may be available but the land element attracts no relief.
• Invest in R&D — R&D tax relief schemes may amplify the deduction on qualifying expenditure funded by the loan.

The loan does not appear in trading profit — only the interest does

A common source of confusion is the treatment of the principal on the profit and loss account. The principal does not pass through the P&L; it goes straight to the balance sheet as cash received and as a creditor. Only the interest is a P&L charge, and only the interest affects corporation tax. If your company draws £500,000 and repays £500,000 over five years, the tax-relevant figures are the annual interest charges and any qualifying fees, not the £500,000 itself.

Understanding this distinction helps directors assess the true after-tax cost of borrowing. Confirm the precise computation for your company with your accountant before drawing conclusions about tax efficiency.