Hourly billing has a structural problem that most in-house buyers have stopped noticing because they have lived with it for so long. The buyer carries all of the scope risk. The firm carries none. If the matter takes three times longer than anyone expected, the firm bills three times more. If the partner pulls in a senior associate, a junior, and a paralegal to "get it across the line," the time entries multiply and the invoice arrives at the end of the month with no warning. The buyer signed up for advice. What they actually bought was an open meter with no posted fare.
This is not a moral problem with law firms. It is a pricing model problem. Hourly billing was designed when matters were small, partners were generalists, and the unit of legal work was a phone call or a letter. It has not aged well. The complexity of modern in-house work, the scale of compliance, the volume of contracting, and the sophistication of the buyers have all moved past it. And yet most engagement letters still default to hourly because that is what the firm's billing system understands.
Fixed-fee engagement letters are the obvious alternative. They are also widely misunderstood. A fixed fee is not a discount on hourly. It is a different product. It transfers scope risk from the buyer to the firm, which means the firm has to do work the buyer never sees: scoping, exclusion-mapping, change-control design. When that work is done well, fixed-fee is the cleanest commercial arrangement in legal services. When it is done badly, it is worse than hourly because everyone now has a false sense of certainty about a number that is going to move anyway.
This post is the operator-voice version of how to make fixed-fee actually hold. What goes in the letter, where it fails, when to refuse to use it, and when it is the right answer by a wide margin. If you want the short version of how we structure it on our side, our how it works page lays out the match-to-engagement flow.
What a fixed-fee engagement letter has to contain to be defensible
A fixed-fee engagement letter is not a one-line quote. It is a small contract for a unit of legal work. If any of the following are missing, the fee will not hold, and the conversation about variations will start within two weeks.
The scope statement is the first item, and it is the one most often written too thinly. A scope statement should describe the deliverable, the matter, and the boundary of the legal question being answered. "Review the supply agreement" is not a scope. "Review the supply agreement dated 14 May between Client and Supplier, mark up against Client's standard position paper attached at Annexure A, and provide a one-page risk summary covering indemnities, liability caps, termination, and IP" is a scope. The difference is whether a third party reading the engagement letter in six weeks could tell what was promised.
Exclusions matter more than the scope statement, because they are where the disputes happen. If you do not exclude negotiation rounds, the firm will assume one round is included and you will assume three are. If you do not exclude calls with the counterparty, the firm will treat each one as a variation. Exclusions should be written in the same plain language as the scope, and they should be specific. "Excludes negotiation with counterparty beyond two rounds of mark-up exchange" is useful. "Excludes additional work" is not.
Deliverables should be enumerated as physical artefacts. A marked-up draft is a deliverable. A risk summary is a deliverable. A two-hour advisory call is a deliverable. "Legal advice" is not. If the firm cannot tell you what they are handing over and on what date, the fee is not really fixed, it is just a number with no anchor.
The change-control mechanism is the part most engagement letters skip, and it is the part that makes the whole structure work. Change-control is the process by which scope amendments are priced, agreed, and signed before the extra work begins. It should say, in writing, that any work outside scope will be quoted as an addendum, that the addendum will state the additional fee, and that the addendum must be countersigned before the firm starts on it. No surprise WIP. No "we'll sort it out at the end." If change-control is missing, the engagement letter has a hole in it, and the hole is the size of the matter.
Payment milestones close the loop. Fixed-fee does not have to mean paid in one tranche. For larger matters, milestones tied to deliverables work better for both sides. On signing, on first draft, on completion. The firm's cash flow improves and the buyer keeps leverage on delivery.
The three failure modes of fixed-fee in practice
Fixed-fee fails in three ways, and the failures are not symmetrical. Two of them hurt the buyer and one of them hurts the firm.
The first failure is under-scoping. The firm quotes a fixed fee that is too low because the partner who priced it underestimated the work, or because the matter turned out to be more complex than the scoping call revealed. The firm eats the margin. From the buyer's perspective, this looks like a win. From a relationship perspective, it is not. A firm that loses money on a matter will be slower next time, more defensive on scope, and more likely to refuse fixed-fee on the next brief. Under-scoping is the firm's problem to solve, but the buyer pays for it on the next engagement.
The second failure is over-scoping. The firm quotes a fixed fee with so much padding that the buyer overpays by a wide margin compared to what the matter actually required. This is the failure mode buyers fear and the one that drives them back to hourly. It usually shows up when the firm is uncertain about the matter and prices defensively, and when the buyer has no benchmark to push back. The cure is published rates and a competitive scoping process, which is why daily rate transparency matters more than people think.
The third failure is under-defined exclusions, which is the most common one and the most corrosive. The fee is reasonable, the scope is reasonable, but the exclusions are vague. So scope creep arrives, dressed up as in-scope work, and the firm starts absorbing it to keep the relationship warm. Three months in, the firm is unhappy, the partner is grumbling internally, and the next brief gets quoted thirty per cent higher with no explanation. The buyer thinks the firm has become expensive. The firm thinks the buyer has become unreasonable. Both are responding rationally to an engagement letter that did not do its job.
The fix for all three failure modes is the same. Write scope and exclusions in the same level of detail. Treat exclusions as a real product surface, not a legal CYA paragraph. And require change-control to be used, not just included.
When fixed-fee is wrong
Fixed-fee is wrong when the unit of work cannot be bounded at the start. This is not a question of preference or culture. It is a question of whether the matter has knowable depth.
True litigation is the clearest example. Discovery scope, the other side's behaviour, court timetables, and witness availability are all outside anyone's control. Pricing a defended proceeding as a fixed fee at the outset means either the firm carries enormous risk and prices it accordingly, in which case the buyer overpays massively, or the firm under-prices and goes back for variations every two months, in which case the buyer ends up with hourly billing wearing a fixed-fee mask. Stage-gated fixed-fees can work for specific phases (pleadings drafted, mediation prepared, brief to counsel), but a single fixed fee for the whole proceeding is almost always wrong.
Regulatory investigations with unknown depth are the same shape of problem. If the regulator's information requests are open-ended and the document population is unknown, the matter cannot be priced as a fixed fee without enormous padding.
M&A diligence on a target with poor data room hygiene is the third common case. If the firm cannot see the data room before quoting, they are pricing a black box. A staged fixed-fee, one for initial diligence sweep, one for full diligence after triage, is workable. A single fixed-fee for "diligence" is not.
The honest answer in these matters is a capped fee, a phase-gated arrangement, or hourly with a budget and a hard reporting cadence. Pretending it is fixed-fee when it cannot be is worse than just billing hourly.
When fixed-fee works brilliantly
The opposite is also true. There is a large class of legal work where fixed-fee is the obvious right answer and the only reason it is not used universally is institutional inertia.
Contract drafting against a known template or position paper is fixed-fee territory. The work is bounded, the deliverable is clear, and the firm has done the same shape of matter a hundred times. Employment matter resolution, from drafting a deed of release to advising on a performance management process, is the same. IP filings, trade mark applications, patent prosecution steps, design registrations, all have well-understood unit costs. Policy reviews, advice memos on a defined legal question, and deal documentation pre-signing are all bounded units of work.
For this entire band of work, hourly billing is a worse product. It introduces uncertainty for the buyer with no corresponding benefit to the firm. A firm that is genuinely confident in its own efficiency should prefer fixed-fee on this work because it lets them capture the upside of being fast. A firm that resists fixed-fee on bounded work is telling you something about either their confidence or their internal cost structure.
Our for buyers page has more on the shape of work that we see priced cleanly on fixed-fee and how the scoping conversation runs.
Change-control: the part everyone skips
If there is one mechanic that decides whether a fixed-fee engagement holds, it is change-control. Change-control is the process by which scope variations are priced, agreed, and signed before any extra work happens. It is boring, it is procedural, and it is the only thing that prevents the engagement from drifting back into hourly behaviour.
A working change-control mechanism has three properties. It is transparent, meaning the additional fee is quoted in the same format as the original fee with the same level of scope detail. It is signed, meaning both parties countersign the variation before work starts. And it has a no-surprise rule, meaning the firm cannot do the work and then ask for the variation afterwards. If the firm starts the extra work without a signed variation, the work is in-scope and not chargeable.
That last rule is the one that does the work. It moves the incentive to flag scope changes from the buyer (who has no way of knowing) to the firm (who knows immediately). Once a firm has to stop work to get a variation signed, scope creep becomes visible. Once it is visible, it stops being scope creep and becomes a commercial conversation, which is what it should have been from the start.
How we handle it on our side
When a brief comes in through our platform, scope is priced at match, not after. The three lawyers who respond to the brief see the same scope statement the buyer sees, and they price against it. The engagement letter is generated from the matched scope, with exclusions, deliverables, and change-control mechanism in the document. Variations go through engagement letter amendments, transparently priced and signed before the extra work begins. There is no hourly fallback. If the matter is genuinely unbounded, we say so at the scoping stage and route it differently, rather than pretending it is fixed-fee.
The mechanics are not magic. They are just the standard fixed-fee discipline written down, applied consistently, and put in front of the buyer before they commit. If you want to see how lawyers experience the same flow on the supply side, our for lawyers page covers it.
Fixed-fee is not a billing trick. It is a different product, and it requires the firm to do scope work the hourly model lets them skip. When that work gets done, the engagement holds. When it gets skipped, the engagement does not, and everyone goes back to hourly with the same complaints they had three years ago.
Brief in, three vetted senior lawyers out, in four hours.
My Legal Connect matches in-house General Counsel with senior Australian lawyers. Pre-cleared conflicts, published daily rates, fixed-fee engagement letters.