Can I Legally Charge Interest on Money Owed to Me? What UK Businesses Need to Know

If you've ever felt frustrated by late payments from clients or customers, you're not alone. Cash flow is the lifeblood of every small business, and waiting on overdue invoices can make things stressful - especially when you're already busy running your operations.

You might be wondering: Can I charge interest on money owed to me? Is there a simple, legal way to encourage clients to pay on time - or get compensated if they drag their feet?

The good news is, businesses in the UK do have the right to charge interest on overdue payments in many circumstances. But there are clear rules around how you do it, the rights you have, and what you need written into your contracts for everything to stand up in court.

In this guide, we'll break down what UK law says about charging interest on unpaid invoices, how to protect your business, and the practical steps you can take to make late payment interest work for you - not against you. Let’s dive in.

Can I Charge Interest on Money Owed to Me in the UK?

The short answer is: yes, UK businesses can often charge interest on outstanding invoices, but there are a few important rules to follow to ensure you're doing it legally.

Whether you’re a sole trader, operate as a limited company, or run a partnership, you can rely on statutory rights and/or contract terms to support your claim for interest on late payments.

There are two main routes:

• Including a clear contract term about interest on late payments
• Using statutory rights under UK law, even if your contract doesn’t mention interest

Let’s explore both.

What Are My Legal Rights to Charge Interest?

UK law protects businesses by allowing them to charge interest on late payments through two key routes:

• Contractual Right: If your written agreement or terms & conditions specify an interest rate (for example, "8% per annum on overdue balances"), that’s the default position for your client or customer.
• Statutory Right: Even if you don’t have a contract clause, you may still charge interest under the Late Payment of Commercial Debts (Interest) Act 1998. This law gives businesses the right to claim statutory interest on late payments in business-to-business (B2B) transactions.

It's important to understand how these work and in what situations each right applies.

How Does Statutory Interest on Late Payments Work?

If you’re dealing with another business (not private consumers), statutory interest lets you charge:

• 8% above the Bank of England base rate, calculated on a simple interest basis, from the day after payment is due until payment is actually made.

For example, if payment was due on 1 June and paid on 1 July, you could calculate interest on the overdue sum for 30 days at the statutory rate.

You can also claim “reasonable recovery costs” for chasing the debt.

But, if your contracts or invoices specify a different interest rate (and it’s not unfairly low), your contract terms will overrule statutory interest.

This statutory right is a default “back-up” - there to help you even if you didn’t get robust terms agreed upfront.

What About Charging Interest to Consumers?

It’s a bit different if you’re dealing with consumers (members of the public, not other businesses).

The Late Payment of Commercial Debts (Interest) Act 1998 applies only to B2B transactions.

If you want to charge interest to consumers for late payment, you must clearly state this in your contract or terms and conditions. If you don’t have this written agreement, you can’t just add interest later.

Consumer protection law also says your interest charges must be “fair and transparent”. Excessive or hidden interest could be considered an unfair contract term and might not be enforceable.

For more on how to write strong payment terms for consumer contracts, see our guide on goods and services agreements.

What Should My Contract Say About Interest on Late Payments?

Having clear, specific contract terms is the best way to avoid disputes later. Your contract or terms and conditions should include:

• When payment is due (e.g., “within 14 days of invoice”)
• What happens if payment is late (e.g., “we reserve the right to charge interest”)
• The interest rate (for example, “interest will accrue daily at a rate of 8% per annum above the Bank of England base rate”)
• Any admin or recovery fees for chasing the debt

By being explicit, you make sure your clients know the rules up front - and you’re much more likely to be able to actually recover interest if a payment is late.

Not sure how to word your terms? Our guide to contract clauses highlights the essentials every professional document should contain.

Step-by-Step: How to Charge Interest on Late Payments

If you want to start charging interest (and collecting it!) when clients or customers pay late, follow these key steps:

1. Check your terms and conditions: Review your contracts, quotes, or invoices to see if you’ve already included a late payment interest clause.
2. Send a formal reminder: If payment is overdue, send a polite reminder detailing the amount owed, reference to your terms, and a specific deadline for payment.
3. Calculate the interest: Use the agreed contract rate or, if there’s no contract rate (B2B only), use 8% over Bank of England base rate. Make sure calculations are clear and transparent.
4. Send an updated invoice: Clearly split out the original amount, the interest charged, and any recovery fees. Be professional and direct, referencing the clause or law that allows you to do this.
5. Pursue legal remedies if needed: If payment (with interest) is still outstanding, you may be able to use a solicitor’s letter, escalate to a debt recovery service, or claim through the small claims court.

For more on debt collection steps, see our in-depth guide to business debt recovery.

Are There Limits or Rules on How Much Interest I Can Charge?

Yes - while you have rights, there are limits to how aggressive you can be when charging interest:

• Contractual rates should not be “grossly unfair.” If the rate is excessively high or structured to be punitive, it may be challenged in court.
• For B2B debts: The statutory rate (8% over base) is seen as fair and reasonable. Higher rates need to be justified and specifically agreed in the contract.
• For consumers: Any contractual right to charge interest must be fair, transparent, and clearly explained before the agreement is made. Complex or excessive charges could breach the Consumer Rights Act 2015.
• You can’t “invent” interest after the fact: If a customer or client wasn’t told about the possibility of interest up front, you can’t suddenly add it after they’re late.

If you’re ever uncertain, get legal advice before taking action - a solicitor can review your terms or help you set up compliant documents.

Do I Need Special Documents or Agreements to Charge Interest?

Having the right paperwork is key. At a minimum, you should have:

• Clear contract or supplier/client terms and conditions with an interest clause
• Professional invoices that reference your payment terms
• Polite, written payment requests and reminders (to keep a clear audit trail)

For recurring relationships, you might also have a goods and services agreement, a service agreement, or separate sales commission agreements - these should all include late payment clauses.

Avoid generic templates - every business is different, and having contracts tailored to your services, payment methods, and customer base will protect you from disputes down the line.

Practical Tips to Reduce Late Payments (and Interest Headaches)

Charging interest is your legal right, but prevention is always better than cure! Here are some proven steps to encourage prompt payment in your business:

• Set clear expectations from day one: Discuss payment deadlines and interest at the start of every new business relationship.
• Include strong payment clauses in all contracts and invoices.
• Send automated reminders a few days before payment is due (not just after).
• Follow up quickly if a payment is missed - politeness paired with firmness works best.
• Don’t be afraid to enforce your terms - a gentle but consistent approach discourages repeat offenders.

If payment disputes drag on, remember that having properly drafted documents will make your case much smoother if you ever need to escalate to a formal debt recovery or legal process.

What Happens If the Other Party Disputes the Interest?

If you’re following your contract and/or statutory rights, you’re on strong legal ground. However, if a customer disputes your charges:

• Double-check the contract - was the interest rate explained and fairly applied?
• Review your calculations for accuracy and transparency.
• Keep records of all communication, including invoices, reminders, and contract documents.
• If discussions fail, consider a formal legal letter or mediation.
• For B2B disputes under £10,000, you can use the small claims court, which is designed to handle such business disputes efficiently.

Disputes can usually be avoided by keeping everything upfront, written, and fair. But it’s wise to know your legal remedies if things do escalate.

Key Takeaways

• You can charge interest on money owed to you in the UK, especially in B2B scenarios - but you must follow clear legal rules.
• Always include a late payment interest clause in your contracts or terms and conditions to make your rights crystal clear.
• For business clients (not consumers), the statutory rate (8% over the Bank of England base rate) can apply even if your contract is silent.
• Charging interest to consumers is only legal if your contract includes this upfront, and it must be fair and transparent.
• Clearly document all stages of chasing payment - from your original terms through to reminders and interest invoices.
• Investing in robust, professionally-drafted contracts now will save you stress and strengthen your legal position if late payments arise.
• If you’re ever unsure, it’s smart to get legal advice from an expert.

---

If you need help setting up clear payment terms, enforcing your rights, or resolving a payment dispute, our team is here to support you. Reach out today on 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat about your business needs.