VAT and Sales Tax for Law Firms: Rule the Line, Not the Invoice

Across jurisdictions and software, the same mistake dominates: a single tax treatment applied to a whole invoice. It survives because most invoices in most industries genuinely are homogeneous, and because most billing software is built for those industries.

A legal statement typically is not. Professional time, a court fee advanced on the client's behalf, and a rebilled expert or translator invoice can each carry a different treatment, on one document the client expects whole. Rule the document rather than the line and you are guaranteed to be wrong about something.

As with cross-border work: none of this is tax advice, treatments differ by jurisdiction and by facts, and the position must be confirmed with your own adviser. What is universal is the shape of the problem.

The distinction most often got wrong is between a true disbursement and a cost the firm incurred for itself.

Money paid on behalf of the client, where the supply is genuinely to the client and the firm is acting as a conduit — a court fee, a registry charge — is commonly treated as outside the scope of tax and passed on at cost. A cost the firm incurred in order to deliver its own service — travel, courier, its own searches — is usually part of the firm's supply and follows the tax treatment of the fee, even where it is itemised separately for transparency.

Itemising a cost separately does not make it a disbursement. That single misunderstanding produces most of the sector's tax errors, and it is a difficult one to correct later, since the client's records now carry the same error.

These are frequently used interchangeably and behave very differently.

• Outside scope — the transaction is not within the tax system at all, as with a true disbursement.
• Exempt — within the system but not taxed, and typically restricting the supplier's ability to recover input tax.
• Zero-rated — taxable at nil, usually preserving input tax recovery.

A system offering only "taxable" and "non-taxable" forces all three into one bucket, which means the firm's return is being prepared from a record that has already lost the distinction the return depends on.

The tax point — the moment a liability crystallises — is not always the moment of payment. Depending on the regime it may be issue of the invoice, completion of the service, or receipt of funds, and for firms holding client money the treatment of a drawdown against a retainer needs care.

This is why an estimate must never share a sequence with a fiscal invoice. If a proforma can become a tax point by accident, the firm is accounting for tax on work that has not been agreed, let alone billed.

Most audits of a professional firm start in the same place: is the numbering unbroken, and can every document in the sequence be produced?

Gaps require explanation. Systems that number by creation and allow deletion of drafts manufacture gaps as a matter of routine. Firms then explain them years later from memory. Separate books — taxable, exempt, proforma, receipts — each unbroken on its own terms is what makes that conversation short.

Invoices are sometimes wrong. The right response is never to edit the issued document, because the client and often the authorities already hold the original.

Corrections happen forward: a credit note or an auditable reissue that references what it corrects, leaving the original in the record. A system that lets an issued invoice be edited in place has quietly made every historical figure provisional, and made the firm unable to demonstrate what a client was originally told.

Tax is ruled per line, not per document, so taxable professional time, an outside-scope disbursement and a rebilled third-party cost can sit on one honest statement, each with its own stored treatment and rate.

Mersal issues from three separate serial books — VAT, exempt and proforma — each with its own unbroken sequence, so an auditor's first question has a short answer. Proformas cannot be paid and never reach a revenue figure, so they cannot become an accidental tax point. Reporting splits rated and exempt work and states tax collected, so the figures line up with what a return needs.

Issued invoices freeze: stored per-line rates and the stamped tax always outrank current firm settings, so changing the firm's rate next year cannot rewrite what a client was charged. Corrections are made by auditable reissue with the original retained, and every step lands in an append-only ledger the application cannot amend.