The Best Payment Reminder App for UK Sole Traders (2026): 6 Tools Ranked on Statutory Interest, GBP Pricing, and Staying in Your Books

Most "best payment reminder app" lists are written for American freelancers. They talk about Zelle, net 30, and state late fee caps, and none of it maps onto a sole trader in Leeds who just wants the £1,200 invoice from March paid.

So this is the UK version. I've ranked six tools on three things that actually matter if you're self employed here: whether they handle the statutory 8% plus Bank of England base rate interest you're legally entitled to, whether they bill you in pounds, and whether you can chase invoices without ripping out whatever bookkeeping you already use for your Self Assessment.

Quick spoiler on the first test: nobody passes it cleanly. More on that below, because it changes how you should pick.

The three tests, and why statutory interest is the awkward one

GBP pricing. Sounds trivial, but a USD subscription means your card issuer adds a foreign transaction fee, your price drifts with the exchange rate, and your accountant asks you about it every January.

Chasing without leaving your books. If you do your bookkeeping in FreeAgent, Xero, or QuickBooks, you don't want a chasing tool that forces you to re-create invoices somewhere else. The best payment reminder app for UK sole traders reads what's overdue and gets on with it.

Statutory interest. Under the Late Payment of Commercial Debts (Interest) Act 1998, you can charge business customers 8% above the Bank of England base rate on overdue invoices, plus a fixed compensation fee of £40, £70, or £100 depending on the debt size. The base rate used is the one in force on 31 December or 30 June, whichever came before the invoice went overdue.

Here's the catch. No tool on this list calculates that for you. They all offer either a flat percentage, a fixed fee, or nothing at all. So what you're really comparing is how easy each one makes it to add a correctly worked-out interest line and mention it in the reminders. Our late fee calculator does the sums, and then the question is where that number goes.

1. Saldetto

What it is: A dedicated chasing tool. You connect it to where your invoices live, it watches for overdue ones, and it sends an escalating sequence of reminders from your own email address until the money arrives.

Statutory interest: You add the interest and compensation fee as a line on the invoice or in the reminder text. Saldetto doesn't compute the base rate for you, but the reminder templates are fully editable, so a "statutory interest now applies from [date]" paragraph is a one-time setup, not a per-invoice chore.

GBP pricing: Flat monthly plan, not per-invoice. Check the pricing page for how you'll be billed in the UK before you commit.

Stays in your books: Yes. This is the main reason it's at the top. Your invoices stay in your accounting software; Saldetto only handles the follow-up.

Who it's for: Sole traders who already have bookkeeping sorted and are tired of the day 7, day 14, day 30 emails.

Where it falls short: It isn't a UK company, so there's no built-in Self Assessment or VAT awareness. If you want one app for everything, it isn't that.

2. Chaser

What it is: UK-built credit control software that plugs into Xero, QuickBooks, and Sage. It's the heavyweight option.

Statutory interest: Same story as everyone else. Flat late fee logic, no automatic base rate lookup. The templates are flexible enough to reference statutory interest.

GBP pricing: Yes, properly in pounds. But it starts at roughly £40 a month at last check, and the plans assume a business with a decent invoice volume.

Stays in your books: Yes, with one of the deepest Xero and QuickBooks integrations around, including payment status syncing back.

Who it's for: A sole trader sending 30+ invoices a month to business clients, or anyone who already uses Xero or Sage and wants chasing baked into it.

Where it falls short: Overkill at £40 a month if you send eight invoices a month. The feature set is built for finance teams, and it shows.

3. FreeAgent

What it is: UK accounting software built for sole traders and small limited companies. It's free if you bank with NatWest, RBS, Ulster Bank, or Mettle. Otherwise it's around £19 a month plus VAT on the sole trader plan.

Statutory interest: Nothing automatic. You add it as a line item manually.

GBP pricing: Yes, and often free, which is hard to argue with.

Stays in your books: It is your books. Reminders are built in and send automatically on a schedule you set.

Who it's for: Sole traders who want one UK app for invoicing, expenses, Self Assessment, and basic reminders.

Where it falls short: The reminders are fixed-schedule and gentle. They don't escalate in tone, and they stop after a few goes. If a client is a chronic late payer, FreeAgent politely nudges them forever.

4. Xero

What it is: The UK's most popular small business accounting software. Plans start around £16 a month for the Ignite tier.

Statutory interest: No automatic calculation. Line item only.

GBP pricing: Yes.

Stays in your books: Built in. Reminders only fire for invoices you emailed from Xero itself, which trips people up if you send PDFs by hand.

Who it's for: Sole traders already on Xero who want the simplest possible setup.

Where it falls short: Reminders are one template per time interval, sent from a Xero address rather than yours, with no "stop chasing, I've spoken to them" nuance. Most people on Xero end up pairing it with something from this list.

5. QuickBooks Online (UK)

What it is: Intuit's UK version, with a Sole Trader plan at roughly £10 a month that handles income tax estimates and Self Assessment prep.

Statutory interest: None built in.

GBP pricing: Yes.

Stays in your books: Built in. Reminders exist but are basic and buried in settings.

Who it's for: Sole traders who want the cheapest UK accounting package with reminders as an afterthought.

Where it falls short: The reminders are the weakest on this list. Fine as a backstop, not as your chasing system.

6. Zoho Invoice

What it is: Free invoicing software with GBP support, recurring invoices, and automated reminders.

Statutory interest: You can set a late fee as a flat amount or percentage, which is closer than most. It still won't track the base rate for you.

GBP pricing: Free, so yes by default.

Stays in your books: No. You'd be creating invoices in Zoho, which means it either replaces your current setup or duplicates it.

Who it's for: Brand-new sole traders with no bookkeeping yet who want something free that chases.

Where it falls short: The moment you've got bookkeeping elsewhere, it becomes a second system to maintain.

How to actually handle the 8% plus base rate with any of these

Since no invoice chasing app for UK self employed workers does the maths, here's the workflow that works with all six:

1. Put the statutory interest wording on every invoice from day one. Something like "We reserve the right to charge interest and compensation under the Late Payment of Commercial Debts (Interest) Act 1998." You don't need the client to agree to it. It's the law.
2. When an invoice goes overdue, run the amount through the late fee calculator with the correct reference base rate.
3. Add the interest and the fixed compensation fee as line items, or issue a separate interest invoice.
4. Make sure your reminder sequence mentions the interest is accruing. Half the point is deterrence.

If you want the wording written out and ready to drop into your terms, the late payment policy template covers it.

The verdict

If you're asking which is the best payment reminder app for UK sole traders, the honest answer depends on where your invoices already live.

• Already on FreeAgent, Xero, or QuickBooks and happy with it? Keep it and add Saldetto on top for the chasing. You get escalation and your own sender address without moving anything.
• Sending high volumes to business clients and already on Xero or Sage? Chaser, if the £40 a month pays for itself. For most sole traders it won't.
• Starting from scratch with a NatWest, RBS, or Mettle account? FreeAgent, free, and accept the reminders are gentle.
• No bookkeeping at all and zero budget? Zoho Invoice until you outgrow it.

And whichever you pick, do the statutory interest yourself. It's the one bit of UK late payment law that works in your favour, and no app is going to claim it for you.