Illustrative cost

£19,000 to £65,000 ex VAT

Typical
£34,000
Duration
About 14 weeks
Effort
44 to 84.5 days

Illustrative estimate, not a quote. Real prices vary.

Worked out from UK freelance contractor day rates in job adverts, with no consultancy or agency margin added. Consultancies and agencies usually charge more.

Source: IT Jobs Watch. Rates read on ; costs computed on .

What is included

  • Conversation design for the most common enquiries
  • A chatbot built on a commercial language model, grounded in approved help content
  • Hand-over to a person and a clear message that the customer is talking to a bot
  • Testing for accuracy, tone and unsafe answers
  • Launch and two weeks of tuning

Deliverables

  • A live chatbot on the website or helpdesk
  • A test report
  • An admin guide for updating content
  • A monitoring dashboard

Assumptions

  • Help content exists and is broadly current
  • An off-the-shelf chat widget or helpdesk integration
  • Model and hosting fees are paid by the client and are not in this estimate

Not included

  • Order or account actions that change customer data
  • Voice and telephony
  • Ongoing model usage fees

Project plan

Phases run one after another, about 14 weeks in all.

Phases, their length and main tasks
PhaseWeeksMain tasks
Discovery and design3Analyse enquiry logs; Design conversations and hand-over; Choose the platform and model
Knowledge preparation1Gather and tidy help content; Agree what the bot must not answer
Build4Retrieval and prompt design; Widget or helpdesk integration; Guardrails and hand-over
Test and launch3Accuracy and safety testing; User acceptance; Go live
Tuning3Review conversations; Fix gaps in content and prompts

Who does the work

Person-days per role in each phase, low and high effort.

Days by phase and role
PhaseRoleDays (low to high)
Discovery and designBusiness analyst3.5 to 7 days
Discovery and designUX designer2 to 5.5 days
Discovery and designAI architect2 to 3.5 days
Knowledge preparationBusiness analyst2 to 5.5 days
Knowledge preparationGenerative AI (LLM) engineer2 to 3.5 days
BuildGenerative AI (LLM) engineer14.5 to 25 days
BuildAI engineer5.5 to 11 days
Test and launchTest engineer3.5 to 7 days
Test and launchGenerative AI (LLM) engineer3.5 to 5.5 days
Test and launchProject manager3.5 to 5.5 days
TuningGenerative AI (LLM) engineer2 to 5.5 days

How the cost adds up

Cost by role: low, typical and high, before rounding
RoleLow (days × 25th percentile)Typical (days × median)High (days × 90th percentile)
Business analyst5.5 × £425 = £2,3389 × £500 = £4,50012.5 × £662 = £8,275
UX designer2 × £406 = £8123.75 × £450 = £1,6885.5 × £588 = £3,234
AI architect2 × £549 = £1,0982.75 × £650 = £1,7883.5 × £850 = £2,975
Generative AI (LLM) engineer22 × £417 = £9,17530.75 × £543 = £16,69739.5 × £825 = £32,589
AI engineer5.5 × £488 = £2,6848.25 × £589 = £4,85911 × £863 = £9,493
Test engineer3.5 × £350 = £1,2255.25 × £438 = £2,3007 × £588 = £4,116
Project manager3.5 × £451 = £1,5794.5 × £540 = £2,4305.5 × £714 = £3,927
Total, rounded£19,000£34,000£65,000

How these estimates are worked out

Effort: for each phase we estimate how many days each role works, as a low and a high case. These are our estimates for a typical project of this kind, not measured data.

Rates: each role's daily rate comes from UK contract job adverts over the last six months, as published by IT Jobs Watch. These are freelance contractor rates as advertised, not what was paid, and not what a consultancy or agency charges.

Low end: the low-effort days at each role's 25th-percentile rate. We use the 25th percentile, not the 10th, because the lowest effort at the cheapest rates gives a floor few buyers would ever meet.

Typical: the mid-point between low and high effort, at each role's median rate.

High end: the high-effort days at each role's 90th-percentile rate.

Totals are rounded to the nearest £500 below £10,000 and the nearest £1,000 above, and exclude VAT. Phases run one after another.

Not included:

  • Software licences, model and hosting fees
  • Travel and expenses
  • Your own staff's time
  • A consultancy's or agency's margin, overheads and risk

Real prices vary with the supplier, the state of your data and systems, how much of the work your own team does, where the work happens and how much risk the supplier carries. Consultancies and agencies usually charge more than these contractor rates, and a fixed price usually costs more than time and materials because the supplier takes the risk.

Sources

Source: IT Jobs Watch: UK contract job adverts quoting a daily rate, 6 months to 15 November 2026. Each role's page was read on . Published under CC BY-NC-SA 4.0.

Day rate sources, one row per role, read on 15 November 2026
RoleIT Jobs Watch pageRates quoted25th percentileMedian90th percentile
Business analystBusiness Analyst1,394£425£500£662
UX designerUX Designer75£406£450£588
AI architectArtificial Intelligence Architect148£549£650£850
Generative AI (LLM) engineerIT Jobs Watch has no "LLM Engineer" or "Prompt Engineer" title with daily rates; mapped to the closest title, Gen AI Engineer.Gen AI Engineer30£417£543£825
AI engineerArtificial Intelligence Engineer384£488£589£863
Test engineerTest Engineer245£350£438£588
Project managerProject Manager1,226£451£540£714

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