When a loan repayment leaves the bank, it rarely represents just one thing. Most repayments contain a portion that reduces the outstanding borrowing and a separate portion that covers interest or other finance charges. Those two amounts belong in different parts of the accounts, and treating them as one combined expense is where things go wrong.

HMRC guidance on financial costs recognises that finance payments can contain both capital and revenue elements that need to be identified correctly. For UK SMEs managing their own bookkeeping — or reviewing what a bookkeeper has done — understanding how business loan repayments and interest should be recorded is the difference between accounts that tell you something useful and accounts that quietly mislead you.

This post sets out how each element of a loan repayment should be treated, why the split matters, and what to check if your loan balance and your lender's records don't agree.

When your business receives borrowed money, the bank balance increases. That does not mean the business has earned income. It has received cash, but it has also taken on an obligation to repay the lender.

If your business receives a £50,000 loan, the records would normally show £50,000 received into the bank and a corresponding £50,000 loan liability. The loan sits on the balance sheet as what the business owes — separate from trading income and separate from any expense.

That opening entry matters because it sets the baseline. Every repayment you make after that should be reducing the liability or covering the cost of borrowing, or both. If the accounts weren't set up that way at the start, the errors compound month after month.

It is also worth confirming that the opening balance in your accounts matches the loan documents before any repayments begin. A discrepancy at the outset is much easier to resolve early than after twelve months of repayments have passed through.

Suppose £2,000 leaves the bank each month. The lender's statement shows £1,600 as principal and £400 as interest. Those two amounts need to go to different places.

The £1,600 reduces the loan liability on the balance sheet. It is a repayment of something the business already owed — not a cost incurred in the period. The £400 interest is a finance cost, recorded separately on the profit and loss account, subject to the tax treatment that applies to the business.

Posting the full £2,000 to an expense code treats the principal repayment as though it were a normal operating cost. That distorts the profit figure and leaves the loan balance higher in the accounts than it should be. The bank will still reconcile — the full £2,000 did leave the account — but the classification is wrong, and the effect shows up across two parts of the accounts at once.

The bookkeeping point applies regardless of business structure. For sole traders, the tax treatment of interest depends on the relevant Income Tax rules. For limited companies, there are separate Corporation Tax rules for loan relationships. Either way, the principal and interest should not simply be combined because they happen to leave the bank as one payment.

The table below sets out the main loan transactions and the questions worth asking about each one.

Arrangement fees and other borrowing costs deserve particular attention. They should be reviewed rather than automatically posted to general bank charges. The correct treatment depends on the business structure, the accounting framework, the nature of the charge, and the finance arrangement. For limited companies, some borrowing costs may fall within the Corporation Tax loan relationship rules. If a fee is material, it is better to establish the treatment when the borrowing is set up rather than leave it to year end.

Hire purchase and other forms of asset finance add further complexity. The records may need to show the asset acquired, the finance liability, repayments of that liability, interest or finance charges, and depreciation of the asset. The bank feed does not explain all of that on its own — you need the underlying finance agreement or repayment schedule to understand what each payment represents.

The loan balance in your accounts should agree with the lender's records, allowing for any timing differences or charges not yet recorded. When it does not, the difference will usually trace back to one of a handful of causes: the full repayment was posted as an expense; interest was not separated; fees were missed; a payment was duplicated; the opening balance was wrong; a payment was posted against the wrong loan; or interest and other charges were added to the borrowing without being recorded.

A small difference is easy to overlook, but it will roll forward month after month if the loan account is not reconciled. The longer it runs, the harder it is to find where the discrepancy started.

The bank feed and the lender's statement serve different purposes. The bank feed tells you what left the account. The lender's statement tells you how the payment was allocated. You need both. Only the lender's statement provides the split required to post the repayment correctly.

It is sensible to review the loan balance when a new loan is taken out, when the interest rate changes, when an additional repayment is made, when the loan is refinanced, when fees are added, when the facility is settled early, and when the year-end accounts are prepared. For loans with regular repayments, periodic reconciliation throughout the year is also useful — you do not need to wait until year end to catch a problem.

You should also keep enough documentation to explain both the original borrowing and each repayment: the loan or finance agreement, lender statements, repayment schedules, interest calculations, arrangement-fee information, bank statements, correspondence about changes in terms, and settlement statements if the loan is repaid early.

Incorrect loan accounting makes monthly reports harder to rely on. If principal repayments are included in expenses, reported profit appears lower than it should. If those repayments are not reducing the loan account, the balance sheet shows more borrowing than the business actually carries.

Both effects matter. An understated profit figure can distort decisions about drawing money from the business, reinvesting, or presenting numbers to a lender or investor. An overstated loan balance gives a misleading picture of how much the business still owes and how far through the repayment schedule it is.

Some accounting software or integrations can support recurring splits between principal and interest, but the figures still need to agree with the loan agreement and lender records. A bank feed by itself does not identify the correct split — it shows the cash movement, not the allocation behind it.

An accountant or bookkeeper can help make sure the finance is set up correctly from the start and that repayments continue to be recorded consistently. That typically includes establishing the opening loan balance, separating principal and interest each period, reviewing lender statements, reconciling the outstanding liability, checking fees and finance charges, reviewing hire purchase arrangements, and confirming the year-end balance.