Business loan affordability starts with the cash your business can spare after essential outgoings, existing finance and a realistic reserve. A lender's maximum offer is not necessarily a sensible borrowing target. This guide shows how to build your own planning estimate before discussing an application.
How do you calculate business loan affordability?
Start with a month-by-month cash-flow forecast. Record receipts when customers are expected to pay and expenses when the money leaves your account. Keep the opening cash balance visible: a profitable business can still run short of cash between paying suppliers and collecting invoices.
For a simple planning exercise:
Cash available before finance = cash receipts − operating payments − tax provision − essential investment − necessary owner withdrawals.
Room for a new repayment = cash available before finance − existing finance payments − chosen cash reserve.
These are budgeting definitions for this guide, not an accounting definition of free cash flow or a lender's underwriting formula. A lender may use a different measure, such as adjusted earnings, and make its own allowances.
Do not count the same cost twice. If salaries are already in payroll, do not subtract them again as owner withdrawals. Sole-trader drawings are cash outflows even though they are not a profit-and-loss expense. Likewise, reserve for a tax bill or include its payment in the relevant month; do not deduct both without reconciling them.
A negative result means there is no spare repayment budget on those assumptions. It does not mean another loan automatically solves the shortfall.
Is the 25–35% repayment rule reliable?
Not as a general UK lending rule. This article previously described 25–35% of net cash flow as a widely accepted repayment ceiling. That claim was not adequately supported and has been removed.
A percentage can be a personal planning choice, but it should not replace a forecast. Two businesses with the same average surplus may need very different reserves because of stock purchases, customer payment delays or equipment replacement.
What DSCR do UK business lenders require?
Debt Service Coverage Ratio compares a defined measure of cash or earnings with debt repayments over the same period. Ask the lender which definition and threshold it uses; do not assume that every lender requires 1.25.
Illustrative DSCR = cash available before finance ÷ total scheduled debt payments.
In this simplified model, £6,000 available before finance divided by £4,000 of total repayments gives 1.5. A result of 1 means the measured cash exactly covers those repayments, with no cushion within that measure. A result below 1 indicates a shortfall.
For illustration only, choosing a planning ratio of 1.5 with £6,000 available would imply £4,000 for total repayments. If existing repayments are £1,000, the remaining amount is £3,000. That calculation is a ceiling under one assumption, not a recommendation to borrow to it.
Keep the numerator consistent. Do not subtract existing debt payments from cash and then include them again in the denominator. Do not mix annual earnings with monthly repayments. A lender's DSCR result may differ from this cash-budget illustration.
Two worked examples: steady trade versus seasonal income
These fictional businesses are not Aarubi clients. All figures are invented solely to explain the arithmetic.
Consultancy with recurring customer payments
A consultancy receives £24,000 in a typical month. Operating payments are £16,000, tax provision is £2,000 and essential investment and additional owner withdrawals total £1,000. That leaves £5,000 before finance.
After an existing £800 repayment and a chosen £1,200 reserve, the planning budget for a new repayment is £3,000. But if a customer pays £4,000 late, available cash falls to £1,000 for that month. A £3,000 commitment would no longer fit. The business must consider cash already held, customer concentration and whether the project can be reduced or staged.
Hospitality business with a quiet quarter
A café's available cash before finance averages £6,000 a month but falls to £2,400 in its quiet period. Existing repayments are £900 and the owner wants to retain £1,000 each month.
| Planning scenario | Cash before finance | Existing repayments | Chosen reserve | Room for new repayments |
|---|---|---|---|---|
| Consultancy: normal receipts | £5,000 | £800 | £1,200 | £3,000 |
| Consultancy: £4,000 receipt delayed | £1,000 | £800 | £1,200 | £1,000 shortfall |
| Café: average month | £6,000 | £900 | £1,000 | £4,100 |
| Café: quiet month | £2,400 | £900 | £1,000 | £500 |
The café's average suggests far more headroom than its quiet month. Testing a fixed repayment against the £500 quiet-month budget is more informative than borrowing against the average alone. Even that £500 is not a safe recommendation: unexpected repairs could absorb it.
How does a monthly budget translate into a loan amount?
You need the repayment schedule, interest basis, term and fees. Multiplying a monthly budget by the number of months overstates the principal whenever interest is payable.
The table below assumes a hypothetical fixed nominal annual rate of 12%, charged at 1% monthly, equal month-end repayments, no fees and no balloon payment. This is not a market rate, APR quotation or Aarubi offer.
| Monthly repayment budget | Approximate principal over 24 months | Approximate principal over 60 months |
|---|---|---|
| £500 | £10,622 | £22,478 |
| £1,000 | £21,243 | £44,955 |
| £2,000 | £42,487 | £89,910 |
The calculation is principal = monthly payment × [1 − (1.01 raised to minus the number of months)] ÷ 0.01. Figures are rounded to the nearest pound.
At £1,000 per month, the 24-month example totals £24,000 repaid against approximately £21,243 borrowed. The 60-month example totals £60,000 against approximately £44,955 borrowed. A longer term supports a larger principal at the same payment, but also increases total interest in these examples.
Obtain the actual schedule, fees and early-settlement terms before deciding. Our business loan costs guide explains the comparisons to make. The British Business Bank's business loan guide also distinguishes fixed and floating rates: a variable-rate payment can change, so a current quotation is not necessarily a lifetime budget.
What documents help demonstrate affordability?
Prepare evidence that lets a provider reconcile the forecast with actual trading. The precise documents and period required vary; ask before gathering or transmitting sensitive records.
- Recent business bank statements and explanations for unusual transactions.
- Management accounts and available annual accounts.
- A cash-flow forecast showing quiet months and payment delays.
- Existing repayment schedules, including hire purchase and agreed tax payments.
- Details of the funding purpose, amount and how the expenditure will help the business.
- Tax commitments, major planned purchases and overdue supplier balances.
- Ownership details and any proposed security or personal guarantee.
See the British Business Bank's application guidance, our bank-statement guide and application checklist.
Do not upload financial documents to a generic enquiry form unless you have been given an appropriate secure submission route.
Do different funding types need different affordability checks?
Yes. A fixed-payment loan needs a fixed-payment budget; sales-linked collections and invoice-backed facilities need a different forecast.
A merchant cash advance collects an agreed share of eligible sales. Collections may reduce when those sales fall, but that does not remove the cost or guarantee affordability. Model the cash remaining after collections, especially when stock and staffing costs do not fall with sales. Review the agreement's collection terms and any guarantees.
A factor such as 1.2 means £1.20 repayable for each £1 advanced under that simplified example. It is not a 20% APR: annualised cost depends on timing and any other charges. Compare the total amount payable as well as the deduction percentage. Read our merchant cash advance costs guide and the British Business Bank MCA overview.
For invoice finance, consider eligible invoices, the advance percentage, service and finance charges, and who bears customer non-payment risk. Releasing an invoice early is not the same as creating additional sales. For equipment funding, compare deposits, instalments, final payments and ownership terms.
New businesses can also consult the government's Start Up Loans programme. This is a personal loan for business purposes with its own checks, not an Aarubi personal-loan service.
What about regulation and personal guarantees?
Do not assume every business finance agreement has the same consumer-credit protections. The FCA's SME finance review identifies business lending of £25,000 or less to sole traders and small partnerships as within its consumer-credit perimeter. Borrower type, purpose, amount and exemptions matter; limited-company lending is generally outside that perimeter.
This is a broad distinction, not a legal assessment of your agreement. Ask the provider which protections apply and obtain independent advice if uncertain. A business being limited does not eliminate personal exposure where a director gives a guarantee. Read our personal guarantee guide before accepting one.
Action Checklist
- Forecast receipts and payments month by month, not just as annual averages.
- Separate unpaid sales invoices from cash already collected.
- Include taxes, essential investment and owner cash needs without double-counting.
- List every existing finance payment.
- Choose and explain a reserve appropriate to your business.
- Stress-test a quiet month and a late customer payment.
- Compare the quoted schedule and total cost, including fees and final payments.
- Ask about security, guarantees, credit searches and applicable protections.
- Discuss assumptions with your accountant or an appropriately qualified adviser.
Discuss the right funding route
Aarubi provides merchant cash advance services and refers other business-loan enquiries where appropriate. We are not promising a loan amount, rate or approval. Use our business finance FAQ to understand the options, or contact Aarubi to discuss your funding purpose and the next steps for a suitable enquiry.
For a wider comparison, see business funding. Bring a realistic repayment budget, not just a desired borrowing amount. This guide is general information, not personalised financial, legal or tax advice.
Editorial update, 13 October 2026: replaced the unsupported percentage rule and universal DSCR claim with transparent illustrations and source links. Learn about the Aarubi editorial team and content policy.
