Affordability modelling is the process a lender uses to work out whether a borrower can sustain a loan's repayments over time, based on income, essential outgoings, and existing debt. It differs from credit scoring, which weighs a borrower's willingness and track record of repayment rather than their present-day capacity to pay.

Affordability modelling sits inside underwriting and credit decisioning, feeding the income and expenditure inputs a decisioning engine or underwriter weighs alongside the credit score before a loan is approved or a credit limit is set. It is a back-office risk control that shapes that decision, not a tool a borrower ever sees or uses directly.

Frequently asked questions

What's the difference between affordability and creditworthiness?

Affordability asks whether a borrower can sustain repayments today, based on income, outgoings, and existing debt. Creditworthiness asks whether they're likely to repay, based on credit history and behaviour. A borrower can be creditworthy but unable to afford a loan right now, or affordable but with a thin credit file. Lenders assess both before approving credit.

What data feeds an affordability model?

An affordability model draws on income (salary, benefits, or self-employed earnings), verified or estimated expenditure, existing debt commitments, and household circumstances such as dependents. Open banking data increasingly supplements or replaces self-declared figures, giving lenders a transaction-level view of a borrower's actual spending rather than an estimate.

Is affordability modelling a regulatory requirement?

In the UK, the FCA's Consumer Duty and CONC rules expect lenders to assess affordability before extending credit, and to be able to show the assessment was reasonable. Equivalent responsible-lending obligations exist in the US and EU, though the specific rules, evidence standards, and thresholds vary by market and product.