How to Reduce Debtor Days: 10 Strategies That Actually Work

What Are Debtor Days and Why Do They Matter?

Debtor days (also called Days Sales Outstanding or DSO) measure the average number of days it takes your customers to pay their invoices. The lower the number, the faster your cash comes in.

The formula is simple:

Debtor Days = (Trade Receivables / Annual Revenue) x 365

For example, if your business has £200,000 in outstanding receivables and £1.2 million in annual revenue: (200,000 / 1,200,000) x 365 = 61 debtor days.

That means on average, you wait two months to get paid for work you've already done.

In the UK, the average debtor days across all industries sits between 50 and 65 days — well above the standard 30-day payment terms most businesses set. For some sectors like construction and professional services, it's even worse.

Every day your debtor days stay high, you're effectively giving your customers an interest-free loan. Reducing debtor days from 60 to 30 on £1 million in annual revenue frees up roughly £82,000 in working capital. That's money you can reinvest, use to cover costs, or simply keep in the bank instead of borrowing.

The 10 Strategies

1. Add Pay Now Links to Every Invoice

Impact: High | Effort: Low | Time to result: Immediate

This is the single highest-impact change you can make. A pay now button on your invoice removes every friction point between "I should pay this" and "I've paid this."

Instead of asking customers to find bank details, open their banking app, type a sort code and reference — they click a link and pay in 60 seconds. Card, bank transfer, Apple Pay, whatever they prefer.

Businesses that add payment links to invoices report 30-50% reductions in DSO. The reason is simple: most late payments aren't disputes or cash flow problems. They're procrastination. Make it easy, and people pay immediately.

This works with any invoicing system — Xero, QuickBooks, Sage, or plain email.

2. Offer Multiple Payment Methods

Impact: High | Effort: Low | Time to result: 1-2 weeks

If your only payment option is bank transfer, you're excluding customers who'd prefer to pay by card, Apple Pay, Google Pay, or Open Banking.

Every missing payment method is a segment of customers who'll pay slower — because they have to do it the hard way. A single payment link that offers multiple methods on one checkout page removes this barrier.

Card payments settle in 1-3 days. Bank transfers can take 3-5. Open Banking payments settle same-day. The method your customer chooses affects how fast you get paid.

3. Shorten Your Payment Terms

Impact: Medium-High | Effort: Low | Time to result: 1-3 months

If your terms are 30 days and your customers routinely pay at 50, try setting 14-day terms. Some customers will still pay late — but "late" on 14-day terms is better than "late" on 30-day terms.

Before shortening terms, make sure you've done Strategy #1. There's no point demanding faster payment if you haven't made it easy to pay. Short terms without a pay-now link is a recipe for frustrated customers and no improvement in cash flow.

For new customers, set the shorter terms from day one. For existing customers, give 60-90 days notice before changing terms.

4. Send Automated Payment Reminders

Impact: High | Effort: Medium | Time to result: 2-4 weeks

A structured payment reminder sequence catches invoices before they become seriously overdue:

• Day -5: Pre-due date reminder (courtesy)

• Day 0: Due today notification

• Day 7: Friendly first chase

• Day 14: Firm follow-up (switch to SMS)

• Day 30: Formal notice with statutory interest reference

Each reminder should include the payment link. The reminder itself costs nothing to send — and the payment link means the customer can pay the moment they read it.

Most accounting software supports basic email reminders. For multi-channel automation (email, then SMS, then WhatsApp), you'll need a payment link provider that supports all channels.

5. Chase Across Multiple Channels

Impact: High | Effort: Medium | Time to result: Immediate

If your collection process is email-only, you're missing 80% of your audience. Email open rates for payment reminders average around 20%. SMS open rates are 98%.

The most effective approach is escalating channels:

1. Email for the initial invoice and first reminder

2. SMS for the second chase (Day 14)

3. WhatsApp for the third chase (Day 21)

4. Posted letter with QR code for formal escalation (Day 30+)

The same payment link works across all channels. See our multi-channel payment collection guide for the full playbook.

6. Run Credit Checks Before Extending Terms

Impact: Medium | Effort: Medium | Time to result: 1-3 months

Prevention is better than cure. Before extending credit to a new customer, check their payment history:

• Companies House — free basic financial data (accounts, filing history, CCJs)

• Credit reference agencies — Creditsafe, Experian Business, Dun & Bradstreet provide detailed credit reports (£5-50 per check)

• Trade references — ask the customer for two or three references from other suppliers

For customers with poor credit history, consider requiring payment upfront or on shorter terms. For large customers with good credit, standard 30-day terms are appropriate.

This won't help with existing debtors, but it prevents future bad debts from entering your book.

7. Invoice Immediately — Don't Delay

Impact: Medium | Effort: Low | Time to result: Immediate

Every day between completing work and sending the invoice is a day added to your debtor days. If you finish a project on the 1st and invoice on the 15th, you've already lost two weeks before the payment clock starts.

Invoice the same day the work is delivered or the service is completed. If your invoicing process involves approvals, draft the invoice before delivery so it can go out immediately.

For recurring services (retainers, subscriptions), invoice at the start of the period, not the end. This is standard practice and most clients expect it.

8. Make Your Invoices Clear and Correct

Impact: Medium | Effort: Low | Time to result: Immediate

Disputed invoices don't get paid until the dispute is resolved. The most common causes of invoice disputes are:

• Wrong amount — mismatched PO number, incorrect hourly rate, VAT errors

• Missing purchase order — many large companies won't process an invoice without a PO number

• Unclear description — "Professional services — March" doesn't tell accounts payable what they're paying for

• Wrong recipient — sent to the project manager instead of the accounts payable department

Fix these and you eliminate the "we can't pay this because..." delay. Check that every invoice has: the correct PO number, a clear description of work, the right VAT treatment, and the correct billing contact.

9. Offer Early Payment Discounts

Impact: Medium | Effort: Low | Time to result: 1-2 months

A 2% discount for payment within 7 days (written as "2/7 net 30") can motivate customers to pay early. On a £10,000 invoice, that's £200 — a cost to you, but less than the cost of waiting 60 days and the associated cash flow impact.

Early payment discounts work best with:

• Large invoices where 2% is a meaningful saving for the customer

• Customers who have the cash but not the urgency

• Recurring relationships where the discount becomes a habit

Combine this with a payment link and you remove the last barrier — the customer gets a discount AND can pay in one click.

10. Escalate Formally When Needed

Impact: Variable | Effort: High | Time to result: 30-90 days

For invoices that remain unpaid beyond 30 days despite reminders, escalate formally:

• Day 30: Send a formal notice referencing the Late Payment of Commercial Debts Act and apply statutory interest

• Day 45: Send a dunning letter by recorded delivery — a Letter Before Action

• Day 75+: File a County Court claim via Money Claim Online (for debts under £10,000)

The key is having a consistent, documented process. Many businesses never escalate because they don't have a defined procedure. Create one, follow it, and your debtor days will fall — partly because you're collecting faster, and partly because customers learn that you follow through.

How to Measure Progress

Track these metrics monthly:

Days Sales Outstanding (DSO)

Formula: (Trade Receivables / Revenue) x Days in Period

This is the headline number. Track it monthly and set a target — if you're at 55 days, aim for 40 within 6 months.

Collection Effectiveness Index (CEI)

Formula: (Beginning Receivables + Monthly Credit Sales - Ending Total Receivables) / (Beginning Receivables + Monthly Credit Sales - Ending Current Receivables) x 100

CEI measures how effective you are at collecting what's owed within your credit terms. A score above 80% is good; above 90% is excellent.

Aged Debt Breakdown

Split your receivables by age bracket:

• Current (not yet due)

• 1-30 days overdue

• 31-60 days overdue

• 61-90 days overdue

• 90+ days overdue

The goal is to keep the 60+ brackets as close to zero as possible. If more than 10% of your receivables are 60+ days overdue, your collection process needs attention.

First-Reminder Resolution Rate

What percentage of invoices get paid after the first reminder? If this is below 40%, your reminders aren't effective enough — check that you're including payment links and sending at the right time.

Quick Wins vs Long-Term Strategies

Start with strategies 1, 2, and 4 — they're low effort, high impact, and you'll see results within weeks.

Common Questions

What's a good DSO target?

It depends on your industry and payment terms. If your standard terms are 30 days, a DSO of 35-40 is realistic and healthy. Below 30 is excellent. Above 50 means your collection process needs work. See DSO benchmarks by industry for UK-specific data.

Will shortening payment terms upset customers?

Some, yes. Give existing customers 60-90 days notice and explain why. Frame it positively: "We're making it easier to pay with new online payment options, and moving to 14-day terms." The pay-now link softens the blow — shorter terms are less annoying when paying is effortless.

Should I outsource collections?

For invoices 90+ days overdue, a debt recovery agency may be more effective than internal chasing. Agencies typically charge 5-15% of recovered amounts. For invoices under 90 days, internal collection with the right tools (payment links, multi-channel reminders) is usually more cost-effective.

How do payment links actually reduce debtor days?

They eliminate friction. The #1 reason invoices are paid late isn't disputes or cash flow — it's inconvenience. Copying bank details, remembering references, logging into banking apps. A payment link reduces "pay this invoice" to one click. That converts "I'll do it later" into "I'll do it now."

Get Started

Payment links are the quickest way to cut your debtor days. No IT project, no software migration, no change to your accounting workflow. Just a link on every invoice.

Shuttle Payment Links work with 40+ gateways, support white-label branding, and can be sent via email, SMS, WhatsApp, or QR code. See how it works.