Invoice Finance Calculator

UK businesses can use this invoice finance calculator to estimate how much working capital unpaid invoices could theoretically support. The core idea is simple: providers typically advance a percentage of an eligible debtor book, then hold back reserves for ineligible invoices, concentration or other facility rules.

A business with £250,000 of eligible unpaid invoices and an 85% advance rate could theoretically access up to £212,500 before provider-specific reserves and fees. Actual availability depends on eligibility, debtor quality, concentration, facility terms and provider underwriting. This is a planning estimate, not a quote.

Enter the face value of unpaid invoices, then subtract any ineligible items such as overdue, disputed or excluded-debtor invoices. Choose an illustrative advance rate, add any concentration reserve, and set an illustrative service fee and annual discount rate. Pick the average customer payment period to see an indicative finance cost over that window.

Review the estimated available funding first — that is the cash this model says could be released now. Then look at the remaining reserve and the indicative cost. To compare the cost of waiting to be paid rather than how much you might access, use the invoice finance cost-of-waiting calculator.

The eligible debtor book is the gross unpaid invoice book minus ineligible invoices. Gross funding is that eligible book multiplied by the advance rate. Estimated available funding is gross funding minus any concentration or additional reserve you enter.

The remaining reserve in this model is the unadvanced share of the eligible book — for example 15% if the advance rate is 85%. That balance is often released later, after customers pay, but it is not guaranteed in full. Fees, disputes, dilutions and provider adjustments can reduce it.

Indicative finance cost is available funding × the annual discount rate × payment days ÷ 365. The modelled service fee is the eligible debtor book × the service-fee rate. Together they are an illustrative total cost for the selected payment period, not a lender tariff.

A business with £250,000 of eligible unpaid invoices and an 85% advance rate could theoretically access up to £212,500 before provider-specific reserves and fees.

Using the calculator defaults — 1% service fee, 7.5% annual discount rate and a 60-day average payment period — the modelled service fee is £2,500 and the indicative finance cost is about £2,620. The unadvanced reserve would be £37,500. Actual availability depends on eligibility, debtor quality, concentration, facility terms and provider underwriting.

Debtor quality and payment history. Providers assess who owes the money and how reliably they pay. A book of creditworthy trade customers is easier to fund than a book of slow or unknown names.

Concentration. If one customer dominates the ledger, providers often cap the advance on that debtor or hold an extra reserve.

Overdue, disputed and excluded invoices. Items outside the facility criteria do not usually attract funding. That is why this calculator lets you deduct ineligible invoices before applying the advance rate.

Sector, payment terms, turnover and facility structure. Some sectors and billing types are harder to fund. Longer payment terms increase funds in use. Whole-turnover, selective and disclosed or confidential structures also change what a provider will advance.

Invoice finance pricing commonly combines a service fee and a discount or finance charge on funds drawn. Utilisation matters: a facility that is drawn for longer, or against slower-paying customers, usually costs more in discount charges even if the service fee is unchanged.

Payment period, facility size, ledger quality and the provider all affect the final price. The rates in this calculator are editable illustrations. Do not treat them as market averages or promised pricing.

Invoice factoring and invoice discounting both release cash from unpaid invoices. The usual difference is who manages collections: the provider more often handles credit control under factoring, while the business usually keeps that control under invoice discounting. Confidentiality and administration also differ, and structures vary by provider.

For a full comparison of collections, visibility, cost and suitability, read invoice factoring vs invoice discounting. For how invoice finance fits cash-flow timing more generally, see invoice finance and cash-flow management.

Recruitment agencies often feel invoice timing more sharply than many SMEs. Temporary-worker payroll may fall weekly while clients pay on 30–60 day terms. As the contractor book grows, the cash required for payroll can grow with it.

Invoice finance may help bridge that gap by advancing a percentage of eligible client invoices. Payroll finance can also be relevant depending on the agency. Start with the recruitment cash-flow gap and recruitment agency finance before treating any structure as a fit.