The verdict in three sentences
A website for a trade association with 300 member companies in London costs between 25,000 and 60,000 GBP in 2026 on the London agency market, including 7,000 to 17,000 GBP for online membership fee management alone. The project takes 12 to 16 weeks and is won or lost on the quality of the website brief: searchable member directory, gated document library, staff roles and acceptance criteria written before the tender. A chief executive who sends a 15-section brief receives comparable quotes, while everyone else receives ranges that vary threefold.
What a trade association site must do that an SME site does not
A trade association serves three audiences at once: members, who want gated content (legal notes, guidance on regulation, policy updates), prospective members, who must understand in two minutes what their subscription buys them, and government and media, who look for the sector's positions and key figures. On top of that sits the secretariat, often 5 to 12 people, who publish, approve and chase renewals.
The three modules that drive the bill are the member directory (search by trade, region, size, accreditation), the document library with access rights by membership class or committee, and subscription management (annual renewal, fee bands by turnover, card or Direct Debit payment, reminders, receipts). The table below gives 2026 orders of magnitude seen on the London market.
| Module | 2026 market budget (GBP, ex VAT) | Timeline | Watch point |
|---|---|---|---|
| Discovery, sitemap, design | 4,000 - 10,000 | 3 - 4 weeks | Workshops with board and staff |
| Institutional site (25 to 40 pages) | 7,000 - 13,000 | 4 - 6 weeks | CMS with approval workflow |
| Searchable member directory | 3,500 - 7,500 | 2 - 3 weeks | Updated by the member directly |
| Gated document library | 4,000 - 8,500 | 3 - 4 weeks | Rights by class or committee |
| Online subscription management | 7,000 - 17,000 | 4 - 6 weeks | Fee bands, Direct Debit, receipts |
| Events and bookings | 1,500 - 4,000 | 1 - 2 weeks | Member and non-member rates |
| Testing, accessibility, launch | 1,500 - 3,500 | 2 weeks | WCAG 2.2 AA and UK GDPR |
| Indicative total | 25,000 - 60,000 | 12 - 16 weeks |
These are market estimates for London agencies, not fixed rates. The gap between the low and high end comes mainly from integration with the existing membership CRM or accounting software and from the number of permission profiles.
The 15 standard sections of the brief
A useful brief runs to 15 to 25 pages. It does not specify the technology on the supplier's behalf, it describes uses, volumes and business rules. Here is the template we recommend.
| No. | Section | Expected content |
|---|---|---|
| 1 | Context and objectives | Association's remit, 3 measurable goals (e.g. +15% members in 2 years) |
| 2 | Audiences and journeys | Member, prospect, journalist, policymaker, staff |
| 3 | Target sitemap | Sections, pages, content to migrate or rewrite |
| 4 | Member directory | Fields, filters, who updates, how often |
| 5 | Members' area | Login, permission profiles, document volume |
| 6 | Subscriptions | Fee bands, payment methods, reminders, accounting export |
| 7 | Events | Bookings, prices, capacity, badges |
| 8 | Content and editorial | Approval workflow, number of contributors |
| 9 | Integrations | CRM, accounting, email platform, optional SSO |
| 10 | Data migration | Member file, document history, redirects |
| 11 | Accessibility | Target WCAG level, accessibility statement |
| 12 | Data protection and security | Lawful basis, retention periods, UK or EU hosting |
| 13 | Hosting and maintenance | Expected uptime, backups, contract length |
| 14 | Planning and governance | Milestones, steering group, single point of contact |
| 15 | Acceptance criteria | Test scenarios, performance thresholds, blocking issues |
Sections 4, 6 and 15 are the ones associations underestimate most. Without a clear rule on who updates a directory entry, it is out of date within six months. Without a defined accounting export, subscription management creates double entry. Without acceptance criteria, delivery turns into a negotiation.
Writing acceptance criteria that protect the association
Acceptance criteria turn a brief into a verifiable commitment. Concrete examples to reuse: a member finds a peer by trade and region in under 3 clicks; a document page loads in under 2.5 seconds on mobile over 4G; a renewal run for 300 members produces 300 compliant receipts and an export your accountant can read; no gated document is reachable without login, including by direct link; the automated accessibility score exceeds 90 on the main templates. Also require a 3-month warranty period after launch during which blocking defects are fixed at no extra cost.
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Helen, chief executive of a construction trade association with 300 member firms in London (an illustrative scenario), currently handles subscriptions by bank transfer and spreadsheet. Her team spends about 120 hours a year on renewals, reminders and receipts, roughly 4,800 GBP of staff time at 40 GBP per loaded hour. With an online subscription module at 12,000 GBP, that drops to 30 hours, saving 3,600 GBP a year. If the new site and directory lift membership by 5% (15 firms) at an average fee of 1,500 GBP, the association gains 22,500 GBP of extra annual income. The subscription module alone pays back in just over three years through time saved, and in under a year if the membership effect holds.
FAQ
Do we need a full brief for a trade association website?
Yes, as soon as the budget exceeds 17,000 GBP. A 15-section document of 15 to 25 pages is enough, and it narrows the spread between quotes from 3 to 1 down to about 1.5 to 1.
How long does it take to write the brief?
Allow 3 to 5 weeks with two internal workshops and sign-off by the board. An independent digital consultant to help typically costs 2,500 to 7,000 GBP in London.
Can members pay their subscription directly on the site?
Yes, by card and Direct Debit, with fee bands by turnover. The module costs 7,000 to 17,000 GBP depending on the accounting integration required.
What accessibility level should we target?
Aim for WCAG 2.2 AA on the main templates. An accessibility audit generally costs 1,500 to 4,000 GBP and should appear in the acceptance criteria.
How many suppliers should we invite?
Three to five agencies, with a 3-week response window. Beyond that, analysing the bids takes more time than the information it adds.
Let's scope your project. Send us your brief or your first notes: we price the scope module by module, with an indicative budget and a realistic schedule. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
