The bookkeeper's guide to contracts and invoicing (UK)

Bookkeeping stands apart from most freelance work in one respect that shapes everything else: it's genuinely regulated. Practising by way of business, you carry duties most freelancers never encounter, and you're trusted with something few clients hand over lightly — access to the inside of their finances, their bank and their accounting systems. That trust, and the compliance that sits behind it, belong at the centre of the arrangement, before the ordinary questions of fees and cancellations. A written agreement makes both concrete, and then handles the everyday business calmly on top.

This guide covers the terms that matter for bookkeeping specifically — the anti-money-laundering supervision and professional-indemnity cover that come with the work, the scope precision that stops an engagement quietly expanding, how you handle a client's systems and their confidential records, and where your liability sensibly ends — then how to price and invoice so you're paid on time.

A quick note first: TrustSolo isn't a law firm or an accountancy, and nothing here is legal advice. Its contract templates are customisable starting points, not documents a solicitor has drafted or reviewed for your particular situation — and for a high-value or unusual engagement, a professional opinion is worth the money.

Why a written agreement matters for bookkeepers

Bookkeeping has a few features that set it apart from other freelance work, and they're worth naming. The first is that you work inside a client's finances — with access to their bank feeds and their accounting software, seeing everything that moves through the business. The second is that you carry real compliance duties: the work is regulated in a way graphic design or copywriting simply isn't. The third is that scope is uniquely easy to misread — clients routinely assume "bookkeeping" covers far more than it does.

None of that is a problem; all of it is a reason to be clear in writing. A written agreement settles the practical questions before they're tested — what you're supervised to do, exactly what's in scope, how their systems are handled, where your responsibility ends — and it reassures a careful client that you take their finances as seriously as they do. Sent before the first month's work, it does that quietly, and marks you out as the professional you are.

Compliance: the part that's genuinely regulated

This is where bookkeeping is different from almost every other freelance discipline, so it's worth stating plainly.

AML supervision is required. If you provide bookkeeping services by way of business, you must be supervised for anti-money-laundering under the Money Laundering Regulations 2017 — professional bookkeeping is named explicitly among the accountancy services that fall within the rules. There are two routes to being supervised. Either you're a member of a professional body that acts as a supervisory authority — the ICB, AAT, ACCA or ICAEW, among others — in which case that body supervises you and you don't register separately; or, if you aren't supervised by such a body, you register directly with HMRC. A narrow exemption exists only where all of your clients are themselves supervised, which is uncommon for a typical freelance bookkeeper, so treat supervision as the norm and that carve-out as the rare edge case. Supervision brings duties with it: carrying out customer due diligence on the businesses you take on, and reporting anything suspicious through a Suspicious Activity Report to the National Crime Agency. The government's guidance on who needs to register for money-laundering supervision is the place to check your own position.

Professional indemnity insurance belongs alongside it. It isn't a blanket statutory requirement for a bookkeeper, but it's expected in the field and required by the professional bodies of their members — and it's what stands behind the liability cap further down this guide. Treat it as strongly-expected good practice rather than an optional extra, and hold cover that's proportionate to the size of the businesses you work with.

TrustSolo's bookkeeping contract template records both — a section confirming you maintain PI cover and the AML supervision the work requires, with evidence available on reasonable request — as a customisable starting point you adapt to your own arrangements. It records the obligation; it doesn't discharge it — being supervised and carrying out the due diligence is your own responsibility. What the agreement does is state the position clearly to the client. You can see how it fits together under contracts.

Say exactly what you do — and what you don't

If one clause earns its keep more than any other, it's scope — the template calls it the most important for good reason. Clients routinely assume bookkeeping includes preparing their Self Assessment or company return, running payroll, or drawing up year-end statutory accounts. It doesn't, unless you say so — and the quiet drift from "keeping the books" into all of that is where an underpriced client appears without anyone deciding it should.

So set out precisely what's in scope — the recurring monthly work you've actually agreed — and list what's excluded so there's no room to assume. The usual exclusions are worth naming explicitly: preparation and submission of Self Assessment or corporation returns, payroll, year-end statutory accounts, audit or assurance, tax planning and advisory, and VAT registration. None of that is off-limits — much of it is work you might happily take on — but it's separate work, quoted and agreed in writing before it starts, not folded into the monthly fee by assumption. Naming the boundary is what turns "could you also just sort the payroll" into a priced piece of work rather than an evening you didn't charge for.

Access, records and confidentiality

Because you hold the keys to a client's bank feeds and accounting software, the agreement should be clear about how that access is handled. It's for the engagement only; credentials aren't shared or passed on; you don't change settings or permissions beyond what the work needs; and access ends when the engagement does — with the client revoking it and keeping their own backups of their records. Sole-purpose, and closed off cleanly at the end.

The client has their side of the bargain too, and it's fair to write it down: they provide their records — statements, receipts, invoices — by an agreed day each month, and respond to your queries within an agreed window, so you can complete the work on time. A monthly turnaround only holds if the information arrives on schedule.

What you see is highly sensitive, so it stays confidential — the financial and personal detail of a business, kept between you and the client and not shared elsewhere. There's one honest carve-out: anti-money-laundering law can require disclosure, such as a report to the National Crime Agency, and confidentiality doesn't override that duty. And when the engagement ends, a clean handover to the incoming bookkeeper — records, reconciliations and working papers — is the professional close, and worth agreeing up front so it isn't negotiated in a hurry later.

Liability: capping what you carry

A fair liability clause keeps your exposure proportionate to what you were paid. The standard shape caps your total liability at the lower of the fees paid over a recent window — twelve months is common — or your PI limit, so the commercial risk you carry tracks the size of the engagement rather than the size of the client's business.

The point that matters most for a bookkeeper sits just beside it. You're not on the hook for HMRC fines, penalties or interest that arise from the client's own inaccurate information or their missed deadlines. You work from the records and figures they give you; the client stays responsible for the accuracy of what they hand over and for the decisions they make on it. That's fair both ways — you answer for your own work, and they answer for theirs — and stating it plainly heads off the client who reads their own late submission as your failing.

Pricing and getting paid

The fixed monthly fee is the standard model for ongoing bookkeeping, and for good reason: it's predictable for both sides, and it suits work that recurs every month. Price it against the real work rather than a round number — the transaction volume, the number of bank accounts, whether VAT or payroll are included, and how tidy the records arrive — and review it as the client grows and the work grows with them. Two other models have their place: hourly suits one-off or catch-up and clean-up jobs, where the effort is hard to predict; and per-transaction or volume-based pricing suits steady, well-defined activity where the count is clear. As a starting reference — not a benchmark — UK bookkeeping work sits at around £20 to £40 an hour, which is also a useful sanity check on what a monthly fee implies per hour. For how each model works in practice, see what UK bookkeepers charge, and the free rate calculator works backwards from the income you need to a sustainable figure.

One point runs the opposite way to most freelance disciplines. Because most bookkeeping clients are businesses — sole traders and limited companies — the statutory right to charge interest and recovery costs on late commercial payments genuinely applies to most of your invoices. That's a real backstop where a payment runs late, in a way it isn't for the tutor or the wedding photographer billing private individuals. The occasional non-business client wouldn't attract the same statutory footing, but for a typical bookkeeper the protection is there.

Your invoice then follows the same rules as any freelance invoice — a unique number, your details and the client's, a clear description, the amount and a due date. Our guide to how to invoice as a freelancer covers exactly what to include; if a payment does run late, late-paying clients walks through the escalation ladder; and for the underlying terms every freelance contract should carry, the six clauses every freelance contract needs is a good companion read.

How TrustSolo helps bookkeepers

TrustSolo runs the business side of your practice — not the client work itself. The bookkeeping contract template gives you a customisable starting point covering scope and its exclusions, the PI and AML section, system access and confidentiality; the invoicing sends your clients an invoice with an online payment link and automated reminders; and a running estimate of your own Income Tax and Class 4 National Insurance keeps your numbers in view as you go.

It's important to be clear about what it isn't. TrustSolo works alongside, not instead of, the Xero, QuickBooks or Sage you use for your clients' books — it isn't client-bookkeeping software, and it doesn't submit anyone's returns to HMRC. Its job is to make your admin quiet and predictable, so your attention stays on the client work. The view tailored for bookkeepers lives at TrustSolo for bookkeepers.

Get the agreement and the invoicing set up once and the business side mostly looks after itself. When you'd like the paperwork to do that, you can start free — no card required.