You sent the invoice three weeks ago. The client still hasn't paid. You've been meaning to send a reminder but every time you sit down to do it, something more urgent comes up.
This is the most expensive 20 minutes you're not spending.
Late payment costs UK small businesses an average of £25,000 per year in cash flow problems and write-offs. And 87% of late payments could have been prevented with a simple, automated reminder sequence.
In this post, I'll show you the exact workflow I built for a plumbing business in Hertfordshire that eliminated their 4-hours-per-week invoice chasing routine. By the end, you'll have a live system that chases your invoices while you're on-site.
Why Manual Invoice Chasing Fails
Before we get into the how, let's be honest about why most business owners don't fix this problem even though they know they should.
Manual chasing is inconsistent. You chase the invoices you remember, when you remember them. You go harder on clients you like less. You forget entirely during busy periods — which is exactly when you need the cash most.
The problem isn't willpower. It's the system.
The 3-Step Automated Invoice Workflow
Here's the workflow we built using Zapier and Xero (the accounting software the client was already using). You can adapt this for QuickBooks, FreeAgent, or any accounting software that has a Zapier integration.
Step 1: Trigger — Invoice Overdue by 3 Days
In Zapier, create a new Zap triggered by your accounting software.
Trigger: "Invoice Overdue" event in Xero (or equivalent) Filter: Only trigger when invoice is overdue by exactly 3 days
This 3-day buffer is important. Sending on the day of due date feels aggressive. Waiting a full week means you're already in cash flow trouble.
Step 2: Send Personalised Email Reminder
Use Gmail or Outlook as the action step. Draft a template that feels personal, not automated.
Template that works:
Hi [Client First Name],
Just a quick note — invoice [Invoice Number] for £[Amount] was due on [Due Date]. I know things get busy, so this is just a friendly reminder.
You can pay online here: [Payment Link]
If you've already sent payment, please ignore this — and let me know so I can mark it off.
Thanks, [Your Name]
The key phrase is "if you've already sent payment, please ignore this." It removes the sting. Clients who have paid feel seen, not accused. Clients who haven't paid have a clear next step.
Step 3: Escalate at 14 Days
Add a second Zap triggered at 14 days overdue. At this point, the tone shifts slightly.
The email now includes:
- The original invoice number and amount
- A statement that this is the second reminder
- Your payment terms (e.g., "our terms are 30 days net")
- A direct call option: "If there's a problem with this invoice, please call me on [number]"
At 21 days, trigger a third email that's more direct and flags potential late payment charges (if your T&Cs include them).
The One Mistake That Kills Invoice Automations
The most common failure I see: using a no-reply email address.
If your automated reminders come from noreply@yourbusiness.com, you've destroyed the personalisation effect. Clients know it's automated. They deprioritise it.
Send from your actual email address (e.g., joseph@primeautomatesystems.com). Zapier and Make both support this via Gmail and Outlook integrations.
Results From the Hertfordshire Implementation
The plumbing business I built this for went from:
- Before: 4 hours/week chasing invoices manually, 28-day average payment time
- After: 12 minutes/week reviewing automated sequences, 11-day average payment time
That's a 61% reduction in payment time. For a business turning over £350K/year, that's an additional £15K+ in working capital at any given time.
What You'll Need to Build This
| Tool | Cost | What it does |
|---|---|---|
| Zapier Starter | £17/mo | Connects your accounting + email |
| Xero / QuickBooks | £14–35/mo | Triggers the automation |
| Gmail / Outlook | Already paying | Sends the reminders |
Total setup time: approximately 2 hours for a first-time user.
Next Steps
If you want to set this up yourself, start with a [INTERNAL LINK: Zapier beginner guide] — it'll take you through connecting your first two apps step-by-step.
If you'd rather have this done for you — including customising the email templates to match your brand voice — [AFFILIATE: Zapier] is the tool I'd use, and I can have it live for you within a week.
Book a free automation audit and I'll tell you exactly what your invoice workflow should look like.
Frequently Asked Questions
Does this work with sole traders? Yes. The workflow works for any business that sends invoices. Sole traders on FreeAgent can use the same Zapier triggers.
What if a client pays between reminders? Add a Zapier filter: check if invoice status is "Paid" before sending. If it is, skip the email. This prevents awkward reminder emails going out after payment.
Can I customise the timing? Absolutely. Some businesses prefer 7/14/21 days. Others go 1/5/14. Adjust based on your industry norms and average payment times.
Will this damage client relationships? Done correctly, no. The tone should always be courteous. Most clients genuinely forget — a polite automated reminder is appreciated, not resented.
What about international clients? If you're billing in different currencies, add a Zapier filter for currency or country, and adjust the email template accordingly.