Day-rate consultancy has a structural incentive problem that rarely gets said out loud: the firm gets paid more the longer the engagement runs. That does not make every day-rate consultancy dishonest, but it does mean the pricing model itself is not aligned with getting you to a working outcome quickly.
What day-rate AI consultancy actually costs
UK AI consultancy day rates span a wide range depending on firm tier: independent consultants and boutiques typically run £500–£2,000 a day, mid-tier firms around £900–£1,600, and Big Four or large enterprise consultancies £1,500–£3,000 or more, often with minimum project fees starting at £100,000. A "discovery phase" alone on a mid-sized engagement can run well into five figures before you have any working output — often just documents, workshops, and a roadmap. That is not necessarily bad value if the roadmap is genuinely good, but it is a real cost commitment before you have proof the approach works, which is exactly the question anyone doing AI project pricing UK research is actually trying to answer.
What fixed-fee looks like instead
A fixed fee AI consultancy prices the outcome, not the hours. Scope is agreed in writing before work starts, the price is fixed regardless of how many days it actually takes, and the incentive flips: the firm now wants to deliver efficiently, because the fee does not grow if the work takes longer. As a reference point, our own packages run from £4,500 for a focused AI readiness assessment up to £15,000 for a production-ready LangGraph agent MVP — both scoped, timelined, and priced before anything starts.
The trade-off worth understanding
Fixed-fee only works when the scope is genuinely well-defined. A vague, open-ended transformation programme is not a good fit for a fixed price, and any firm quoting one for that kind of engagement is either padding the number heavily or planning to renegotiate scope halfway through. The honest use case for fixed-fee is a specific, well-bounded problem: one workflow automated, one proof of concept built, one readiness assessment delivered. For genuinely open-ended, multi-year transformation work, a different commercial structure is usually more honest for both sides.
What to ask a prospective AI consultancy
Ask what happens if the engagement runs over. A day-rate firm bills you more. A fixed-fee firm absorbs it, which is precisely why a fixed-fee firm scopes carefully before committing to a number, rather than after. If a consultancy will not give you a fixed price for a well-defined deliverable, that itself is worth treating as information.
Where this fits for clients
This is how we price everything at Kelriva — three fixed-fee packages, each scoped in writing before work starts, no day rates and no retainers required. If you are comparing quotes and one of them is a fixed number with a defined deliverable, that is usually the easier one to say yes to.