Accounting practice fees: fixed monthly, per task or a mix?

The biggest financial problem for an accounting practice isn’t low prices. It’s that the monthly fee was agreed in 2019 and the client has tripled their paperwork since then — without that conversation ever taking place.

Fees in this profession drift away quietly, because the work grows gradually and never reaches a single point that justifies a discussion. The only way to stop it is to know how many hours each client eats up.

The three models

• Fixed monthly fee: covers the recurring work — bookkeeping, VAT, payroll, regular filings. Predictable for both sides.
• Per task: for anything that doesn’t recur — registering a business, changes, a personal tax return, certificates, payment arrangements, audits.
• Mixed: a fixed fee for the flow, a separate charge for the one-offs. This is the model that works for most practices, as long as what the fixed fee includes is written down.

How to work out the fixed fee

Not from the type of books. Two clients on simple single-entry books can differ by five hours a month. The fixed fee comes from four variables:

1. Volume of documents per month — the main driver of time.
2. Number of employees on the payroll and how stable they are.
3. The state of what arrives: an organised file or a carrier bag. The difference can easily be double the time.
4. Special features: intra-EU transactions, multiple branches, cash registers, special schemes, grants.

Take the practice’s hourly cost (fixed overheads + salaries + your own salary, divided by the truly productive hours), multiply by the client’s estimated hours and add a margin. A client who needs 6 hours a month, at a practice with an hourly cost of €30, cannot be on a €120 fixed fee.

What the fixed fee doesn’t include — in writing

This is the list that prevents friction. Not because you’ll charge for everything, but because when you do charge, it won’t come as a surprise:

• Personal tax returns for partners and their relatives.
• Late and amended filings caused by the client’s delays.
• Representation and support during a tax audit.
• Debt arrangements, certificates, attestations, files for a bank or a grant application.
• Changes to the business register, business registrations and closures.
• Repeatedly chasing documents that were never sent.

That last point deserves a rule of its own

Chasing documents is the profession’s invisible work. It doesn’t appear on any invoice, no client acknowledges it, and in a practice with forty clients it takes up a whole person.

You don’t need to charge for it from day one. You need to measure it and have a written term saying that beyond a certain point it’s chargeable. The mere existence of the term is usually enough to reduce it.

The fee review: once a year, with figures

The difficult conversation becomes easy when it isn’t a matter of opinion. “In 2024 you had 180 documents a month and 4 employees; this year you have 460 and 11” isn’t a price increase — it’s a statement of fact.

1. Set a fixed review period, at the start of every year, for everyone. That way it isn’t personal.
2. Write volume bands into the agreement: up to 150 documents, 151–350, and so on. The increase becomes automatic and indisputable.
3. Give notice beforehand, not with the first invoice of the new year.

Where the profit leaks

• The client who has been paying the same fixed fee since 2019.
• The hours from April to July that were never billed anywhere.
• The free advisory chats that, added together, amount to days.
• Unpaid fees that run for months because the client is an “old friend”.
• Late filings that are redone without charge.

In TaxPro, every task is logged on the client record with its time, and the outstanding balance updates itself — so the annual fee review is based on numbers instead of impressions.

Conclusion

Build the fixed fee on volume, not on the type of books. Write down what’s excluded. Set bands so that increases are a rule rather than a negotiation. And measure hours per client — it’s the only way to see which clients are subsidising the rest.