Unpaid Invoices
Outstanding amounts for goods or services provided to another business.
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Business & Commercial Claims Calculators
Explore free UK business claims calculators for late payment interest, commercial debt recovery costs, overdue invoices, breach of contract, business interruption losses and commercial rent arrears. Understand the relevant calculation methods, financial evidence and legal rules that can affect commercial claims.
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Business & Commercial Claim Calculators
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6 calculators found
Browse UK commercial calculation tools
Late Payments
Late Payment Interest Calculator
Calculate illustrative statutory interest on qualifying late commercial payments using the appropriate Bank of England reference rate, 8 percentage-point addition and days overdue.
Late PaymentsCommercial Debt Recovery Costs Calculator
Identify the £40, £70 or £100 statutory fixed-sum recovery charge for a qualifying overdue commercial debt, plus any separately recoverable reasonable costs.
Late PaymentsUnpaid Invoice Interest Calculator
Organise unpaid invoice balances, payment dates and interest calculations. Compare the applicable contractual or statutory interest basis without double counting.
Contract ClaimsContract Breach Loss Calculator
Estimate documented commercial losses linked to a contractual breach, considering additional costs, lost net profit, mitigation, savings and applicable contractual limits.
Business LossBusiness Interruption Loss Calculator
Estimate interruption-related net financial losses using lost contribution, avoided costs, extra operating expenses and recoveries. This is not an insurance policy calculator.
Commercial PropertyCommercial Rent Arrears Calculator
Organise outstanding commercial rent instalments and payments, with lease-based interest where legally applicable. Rent arrears are not automatically subject to B2B invoice interest rules.
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Business and Commercial Disputes
Common Types of Commercial Financial Claims
Business claims can arise from unpaid obligations, contractual failures or disruptions that cause measurable financial loss. The correct calculation depends on the type of claim.
Late Payment Interest
Statutory or contractual interest on qualifying overdue debts.
Debt Recovery Costs
Fixed statutory compensation and eligible additional recovery expenses.
Contract Disputes
Financial losses potentially caused by a failure to meet contractual obligations.
Business Interruption
Lost financial contribution and additional costs from operational disruption.
Commercial Rent
Unpaid lease instalments, relevant credits and contractual interest.
UK Late Payment Legislation
How Is Late Commercial Payment Interest Calculated?
The Late Payment of Commercial Debts (Interest) Act 1998 can provide a right to statutory interest on qualifying debts arising from business contracts for supplying goods or services.
Statutory Interest Rate
The statutory rate is generally the Bank of England reference rate plus eight percentage points. The reference rate is fixed for relevant six-month periods rather than changed each time Bank Rate moves.
Six-Month Reference Periods
The Bank of England base rate on 31 December is used for the following January to June period. The base rate on 30 June is used for the following July to December period.
When Does Interest Start?
For a qualifying debt, interest generally starts on the day after the legally relevant payment date. Where no payment date is agreed, a statutory 30-day period generally applies with reference to invoice receipt and delivery or performance.
Calculating Daily Interest
Statutory late-payment interest is simple interest. A calculation uses the outstanding debt, annual statutory rate and the eligible number of late days. Part-payments and relevant rate periods need to be handled correctly.
Illustrative simple interest formula
Interest = Debt × (Annual rate ÷ 100)
× (Late days ÷ 365)
Contractual Interest vs Statutory Interest
A contract may provide a separate substantial remedy for late payment. Its terms can affect whether statutory interest applies. The two rates should not automatically be added together.
Does This Apply to Consumer Debts?
The commercial late payment regime is not a universal interest rule for debts owed by ordinary consumers. It targets qualifying business and public-sector supply transactions.
Commercial Debt Recovery
What Fixed Debt Recovery Costs Can a Business Claim?
Where statutory interest arises on a qualifying late commercial debt, legislation can also provide a fixed-sum recovery payment. The amount depends on the debt size.
Debts Below £1,000
Fixed recovery amount for a qualifying commercial debt of less than £1,000.
£1,000 to £9,999.99
Fixed recovery amount for qualifying debts from £1,000 up to but excluding £10,000.
£10,000 or More
Fixed recovery amount for a qualifying debt of £10,000 or above.
Important:
The fixed sum
is available where
the statutory requirements
are satisfied and
is not automatically
charged repeatedly
for the same
late payment. Reasonable
recovery costs beyond
the fixed sum
may also be
recoverable to
the extent permitted
by the legislation.
Invoice Recovery Calculations
How to Calculate Interest on an Unpaid Business Invoice
Unpaid invoices can affect a business's cash flow and create additional collection costs. A useful invoice calculation starts with the outstanding principal and applicable payment terms.
Confirm the Invoice Value
Check what goods or services were supplied and the amount payable. Where applicable, statutory commercial interest is calculated using the qualifying unpaid invoice amount including VAT.
Establish the Due Date
Determine whether the contract specifies payment after 14, 30 or another number of days. If no term is agreed, apply the relevant statutory rules rather than assuming an arbitrary deadline.
Check Which Interest Basis Applies
A contract may contain a valid late-interest clause. If the applicable commercial statute instead supplies the remedy, statutory rates and qualification requirements must be used.
Partial Payments
Where a debtor makes part-payments, interest on the remaining outstanding balance may need to be calculated over separate periods. A single original principal for the entire delay can overstate interest.
Disputed Invoices
A genuine dispute about supply, performance or the amount owed requires individual attention. The Small Business Commissioner's guidance warns against using its late-payment calculator for invoices withheld because of a dispute.
Commercial Contract Damages
How Is a Breach of Contract Loss Calculated?
A business may suffer financial loss when another party fails to fulfil a contractual obligation. Whether damages are payable depends on the terms of the agreement and the applicable legal principles.
Financial Position Without the Breach
A common approach compares the financial position the claimant would probably have occupied if the contract were properly performed with the actual position after the alleged breach.
Direct Additional Costs
Recoverable loss may include qualifying additional costs incurred to obtain substitute goods, complete services or remedy the consequences of a failure.
Lost Profit vs Lost Revenue
Lost sales revenue should not automatically be treated as lost profit. A calculation must account for costs the business would otherwise have incurred to generate those sales.
Foreseeability and Remoteness
Contract damages are subject to limitations on the types of loss that may be recovered, including whether the loss falls within the parties' reasonable contemplation and the legally relevant scope.
Duty to Mitigate
A claimant is generally expected to take reasonable steps to reduce avoidable loss. A worksheet should account for saved expenditure, replacement transactions and relevant recoveries.
Contractual Liability Limits
Some contracts contain exclusions, liability caps or agreed damages provisions. Whether these are valid and enforceable requires review of the actual agreement and law.
Illustrative financial loss model
Net loss = Supported additional costs
+ Qualifying lost profit
− Saved costs − Recoveries
Business Financial Loss
Business Interruption Loss Calculations Explained
A business interruption may affect trading income, operating expenses and profitability. A financial worksheet can estimate the resulting loss across the relevant disruption period.
Establish Expected Trading
The business may use relevant historic sales, seasonal trends, contracted orders and other evidence to assess expected activity without the interruption.
Compare Actual Trading
Actual revenue during the disrupted period can then be compared with a reasonable expected figure. This difference alone is not always the compensable loss.
Account for Avoided Costs
If the business did not incur costs it would ordinarily have paid to generate the missing revenue, those savings should be reflected in a net loss calculation.
Additional Operating Costs
Reasonable additional expenditure to continue trading, relocate temporarily or reduce disruption may be relevant where supported by evidence.
Recovery and Mitigation
Any replacement income, saved expenses, insurance recoveries or other applicable payments should be accounted for appropriately.
Insurance Is a Separate Assessment
This calculator provides a general business loss worksheet. An insurance claim depends separately on policy coverage, definitions and the insured indemnity period.
Commercial Property Payments
How Are Commercial Rent Arrears Calculated?
Commercial rent arrears arise when a tenant has not paid rent instalments due under the applicable commercial lease. An accurate calculation starts with the lease, rent schedule and payments received.
Review the Rent Schedule
Identify the dates on which rent was due, whether monthly, quarterly or under another valid arrangement. Rent reviews, concessions and variations may affect the amount.
Calculate Outstanding Instalments
List each unpaid rent instalment separately, then deduct applicable payments, credits or adjustments. The remaining balance provides an illustrative arrears total.
Interest Under the Lease
Some commercial leases contain interest clauses that apply to overdue rent. The applicable rate, grace period, calculation basis and enforceability depend on the lease and law.
Rent Is Not a Standard B2B Invoice
The statutory commercial late payment regime principally concerns qualifying contracts for supplying goods or services. Ordinary commercial rent should not automatically attract the statutory base rate plus eight percentage points or its fixed recovery charges.
Service Charges and Other Sums
Commercial leases may separately require service charges, insurance contributions or other payments. These should be identified rather than included as ordinary rent without checking the relevant legal definitions.
Commercial Rent Arrears Recovery
In England and Wales, the Commercial Rent Arrears Recovery procedure, known as CRAR, can apply in certain qualifying commercial lease situations. It has statutory conditions and is distinct from simple rent arrears arithmetic.
Basic arrears worksheet
Rent arrears = Rent legally due
− Payments − Applicable credits
Financial Claim Factors
What Affects a Business or Commercial Claim Value?
Financial calculations depend on the legal basis of the claim and supporting documentary evidence.
01
Agreement Terms
Relevant contracts, payment dates, interest clauses and limitations.
02
Outstanding Principal
Verified sums legally due and not yet paid.
03
Relevant Dates
When obligations arose, payments became late and losses occurred.
04
Financial Evidence
Invoices, records, accounts and documentation of actual losses.
05
Recoveries and Mitigation
Part-payments, replacement income, saved costs and reimbursements.
06
Legal Recoverability
Liability, causation, applicable statutory rules and contractual limitations.
Commercial Debt Recovery Process
How Can a Business Recover an Overdue Payment?
If a customer or another business has not paid an agreed invoice, the first step is to establish the amount due and identify the appropriate recovery route.
Verify the Debt
Check the contract, invoices, delivery or service records and any payments received. Confirm whether the debt is disputed.
Contact the Customer
A payment reminder or formal demand can identify the unpaid amount, due date and relevant interest or recovery costs. Communications should be accurate and professional.
Consider Negotiation
Businesses may agree a settlement or payment plan. Any revised terms should be recorded clearly, including treatment of interest and recovery costs.
Small Business Commissioner
The Office of the Small Business Commissioner provides guidance and can consider certain late-payment complaints by eligible small businesses against larger customers. Eligibility restrictions apply.
Court Proceedings
Where a dispute cannot be resolved, civil court action may be available. The appropriate pre-action process, jurisdiction and limitation rules require separate consideration.
Insolvent Debtors
If the debtor is insolvent, ordinary recovery methods may not be appropriate. The creditor may need to participate in the relevant insolvency process instead.
How It Works
How to Use Our Business Claims Calculators
Select the correct financial calculation, provide the relevant figures and review the result with its legal assumptions.
Choose a Calculator
Select late payment, debt costs, unpaid invoices, contract losses, interruption or rent.
Enter Financial Data
Provide verified principal amounts, dates, relevant interest rates or business loss figures.
Review the Breakdown
Check the amount, calculation method, qualifications and official sources before using the result.
Related Compensation Resources
Explore Related Calculator Categories
Explore financial disputes, professional negligence and insurance-related calculations.
Frequently Asked Questions
Business & Commercial Claims FAQs
Common questions about commercial debts, late-payment interest, recovery charges and business losses.
How much interest can I charge on a late commercial payment?
For qualifying UK commercial supply debts, statutory interest is generally eight percentage points above the applicable Bank of England reference rate. Contractual remedies may affect the entitlement.
How is late payment interest calculated?
Simple interest is calculated from the qualifying unpaid principal, the relevant annual rate and eligible overdue days. Historical reference-rate periods and part-payments should be considered.
Can I claim £40, £70 or £100 for debt recovery?
Qualifying statutory debts can attract a fixed recovery payment of £40 for debts below £1,000, £70 for debts from £1,000 to below £10,000, or £100 for debts of £10,000 or more.
Does statutory late payment interest apply to every invoice?
No. The regime concerns qualifying commercial contracts for supplying goods or services. The transaction, contract terms, payment conditions and applicable law matter.
Can I add statutory interest to contractual interest?
Not automatically. A contractual remedy can affect whether the statutory interest regime applies. Review the agreement and the legal rules to avoid double counting.
Does the unpaid invoice calculation include VAT?
Under the applicable late commercial payment rules, the calculation generally uses the qualifying invoiced amount, including VAT where VAT is properly chargeable.
How is compensation for breach of contract calculated?
A financial assessment may include qualifying additional costs and lost net profits, adjusted for saved expenditure, mitigation and recoveries. Legal causation, remoteness and contractual limits remain important.
How do you calculate business interruption losses?
A worksheet can compare expected and actual trading, account for variable costs avoided and add qualifying additional operating expenditure. Recoverability and insurance coverage require separate assessment.
Can a landlord charge 8% plus base rate on commercial rent arrears?
Not automatically. Commercial rent is not ordinarily treated as a qualifying business invoice for goods or services. The lease and other relevant legal provisions determine whether interest is payable.
Can a business claims calculator guarantee a recovery or payment?
No. Calculators illustrate financial arithmetic, but cannot establish that a debt is enforceable, a contractual breach occurred or a particular loss is legally recoverable.
Official UK Commercial Claims Resources
These sources explain commercial payment deadlines, statutory interest, debt recovery payments, contract principles and commercial rent recovery. Reviewed 9 November 2026.