1. Start with the commercial goal, not the design
Agencies cannot price "a nice modern website". They can price "a site that generates 20 qualified enquiries a month from three service pages". Write down what the site must achieve in the first year — enquiries, online bookings, sales, recruitment applications — and how you will measure it. Everything else in the brief flows from that.
2. Describe your audience and what they need to see
Say who is buying, how they buy and what usually blocks the sale. If most of your buyers are procurement managers who need to see accreditations and case studies before they enquire, the site needs those sections and someone needs to write them. That is a cost item, and it belongs in the brief.
3. List the pages and features explicitly
Scope creep is the single biggest cause of overspend. Give a page list (home, about, three service pages, case studies, blog, contact) and a feature list. Be specific about anything that is not a plain content page:
- Enquiry forms and where submissions should go
- Online payments or bookings, and which provider
- Customer logins or gated content
- CRM, email marketing or accounting integrations
- Multi-language or multi-location versions
- Blog or news section you will update yourself
4. Say who is providing content and images
Most late websites are late because the content never arrived. State clearly whether the agency is writing copy, sourcing photography and creating graphics, or whether you are supplying them. If you are supplying, commit to a date. If they are, ask for the number of pages and rounds of revision included.
5. Be honest about budget and deadline
Withholding your budget does not get you a cheaper quote; it gets you a proposal aimed at the wrong specification. Give a range. If there is a hard date — a trade show, a funding round, an office opening — say so, because it changes how the agency resources the job.
6. Cover the technical and legal essentials
- Who owns the design files, code and content when the project ends
- Which platform will be used and whether you can edit pages yourself
- Where the site is hosted and what it costs annually
- Accessibility standard expected (WCAG 2.2 AA is the sensible baseline)
- UK GDPR: cookie consent, privacy policy and where form data is stored
- Core Web Vitals or page speed targets
7. Ask what happens after launch
A website is not finished on launch day. Ask every agency to quote separately for aftercare: security updates, backups, hosting, small content changes and support response times. Compare those annual figures alongside the build cost — a cheap build with an expensive lock-in contract is rarely the cheaper option.
A one-page brief template
You do not need twenty pages. Send agencies a single document covering: business overview, goals and how they are measured, target audience, page list, feature list, content and imagery ownership, examples of sites you like and why, budget range, target launch date, and the technical and legal requirements above. Send the identical document to every agency so the quotes are genuinely comparable.
Next step
Once your brief is written, shortlist three agencies rather than ten and ask each for a fixed-price proposal against it. You can find vetted UK web design agencies in the web design category, or read our guide on how to compare supplier quotes before you make the decision.