Audit engagement management software for a London firm: cost and timeline (2026)

The verdict in three sentences

An audit firm is judged on its ability to evidence its work, not just to do it: during an ICAEW Quality Assurance Department or FRC review, a poorly documented file weighs as much as an audit error. Custom audit engagement software with work programmes aligned to ISAs (UK), a review workflow and locked archiving costs 35,000 to 65,000 GBP in 2026, over 5 to 6 months. Against 100 to 170 GBP per user per month for a market platform, the choice depends mostly on the firm's own methodology and the time horizon you calculate over.

What the software must track, standard by standard

The partner of a 14-person firm handling 180 engagements must be able to show, for each engagement, who did what, when, and who reviewed it. ISAs (UK) structure the file: understanding the entity, risk assessment, materiality, procedures, conclusions. The software turns these requirements into mandatory steps.

File assembly is the point firms underestimate: a file modified after the deadline is a direct finding. The software locks the file automatically and logs any later access.

Custom build or market platform: the 2026 calculation

Market audit platforms are solid and already embed ISA methodology. A custom build makes sense when the firm has its own methodology, specific engagements (charities, public sector, public interest entities) or a strong need to integrate with its practice management and time recording tools.

Over 5 years, the two options overlap. Custom wins if the firm grows (each new hire adds no licence) or if it treats its methodology as an asset.

Timeline of a 5 to 6 month project

Discovery takes about 4 weeks: modelling work programmes, roles (associate, senior, manager, partner, engagement quality reviewer) and approval workflows. Development runs for 3 months with a demo every 2 weeks. The pilot covers 10 real year-end engagements, ideally outside the January to April peak. Rollout to all 180 engagements follows, including migration of permanent files.

Mini case study

James, partner of an audit firm in London, has 14 users. A market platform at 140 GBP per user per month would cost 23,520 GBP a year, or 117,600 GBP over 5 years. He is assessing custom software at 52,000 GBP, with 950 GBP per month of maintenance, or 109,000 GBP over 5 years.

The financial gap is modest, about 8,600 GBP over 5 years. The deciding argument lies elsewhere: the firm expects to save 25 minutes of review per engagement thanks to its own work programmes, 75 hours a year across 180 engagements. At 130 GBP per partner hour, that is 9,750 GBP a year of freed-up time. These figures remain estimates to be validated during the pilot.

FAQ

How much does custom audit engagement software cost in 2026?

For a firm of 10 to 20 staff, budget 35,000 to 65,000 GBP as a ballpark, plus 700 to 1,300 GBP per month for maintenance and hosting. The project takes 5 to 6 months.

Will the software comply with ISAs (UK)?

Work programmes are built from ISAs (UK) and the firm's methodology, then approved by a partner. Final compliance remains the firm's responsibility; the software provides the documentary evidence.

How do we handle file assembly after the report?

The file locks automatically 60 days after the report date. Every later access is recorded in a tamper-proof log retained for at least 6 years.

Where should engagement data be hosted?

UK hosting with ISO 27001 certification costs 130 to 350 GBP per month. Data encryption and two-factor authentication are essential.

When should we start to avoid busy season?

Ideally in May or June, for an autumn pilot on non-December year-ends. Starting in January is not advised: teams are fully booked on December year-ends.

Let's scope your project. Send us your user count, engagement count and current work programmes: we will price the software, hosting and a timeline outside busy season. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.