A buyer's cost-register method for web design commissions

There is no authoritative England-wide tariff for a web design agency. A useful budget therefore starts with the service being bought, not a supposed average price. Record each quantity, billing unit, currency, VAT treatment, term and source date, then add the buyer's own labour and the cost of operating, changing and eventually leaving the service.

This guide was prepared on 6 September 2026 from UK government and regulator records. The public-sector methods cited below are useful disciplines for private buyers, but they do not bind every English business. A finance lead, accountant, procurement specialist and solicitor must settle the treatment of a real purchase.

What to take away

Define the website before asking for a price

Two proposals called "website redesign" may cover different work. One could stop at visual files. Another might include research, copy, code, hosting, migration, staff training and post-launch support. Comparing their totals would conceal more than it reveals.

Write an acceptance brief first. It should identify:

Government Digital Service guidance on choosing technology recommends retaining control of data, reducing lock-in and allowing later changes. Those are sensible questions for an England buyer even though the page addresses government services. They turn vague future expense into requirements that suppliers can answer.

Build a whole-life cost map

The price on an agency proposal is only one part of the commitment. The Cabinet Office publishes Should Cost Modelling tools for public contracting authorities, but they are not a price book for private websites.

Use the same discipline: describe the requirement, expose assumptions and model costs over the relevant life.

Use a register with one row per cost. Do not enter a number until its basis is known.

A worked placeholder budget shows the method end to end. The figures are placeholders only, not actual supplier prices.

The buyer then adds recoverable VAT, internal displaced cost and an exit estimate. The method, not the placeholder figures, is what transfers to another brief.

Classify each row as fixed or variable, then as one-off or recurring. A research workshop may be a one-off fixed commitment. Hosting could recur and vary with a defined usage measure. Those labels describe cost behaviour, not whether the expense is worthwhile.

Separate cash, economic cost and tax

Maintain distinct totals for different decisions:

HM Treasury's Green Book 2022 is government appraisal guidance that distinguishes financial impact from wider economic costs and benefits and asks decision makers to consider uncertainty.

HMRC administers VAT. At the time of writing, the standard UK VAT rate is 20% and the VAT registration threshold is £90,000 of taxable turnover. VAT registration is governed by the VAT Act 1994 and related regulations; HMRC's VAT Notice 700/1, Who should register for VAT, explains registration. Leave recoverability blank until a qualified reviewer checks the transaction.

HMRC's VAT Notice 700, The VAT Guide, explains invoice requirements, including a clear description of the charge, supply date, amounts and VAT where applicable. GOV.UK says VAT-registered suppliers must show VAT separately and apply the correct current rate on covered sales in its charging VAT guidance. These pages do not decide a buyer's entitlement to recover input tax.

Match the pricing structure to the uncertain work

Common structures include a fixed fee for a defined scope, time-based charging, a capacity retainer, usage billing for a platform or an outcome-linked component. In England, agencies usually express those choices as a fixed project fee, a day or hourly rate, a monthly retainer, a platform licence with usage tiers, or a success component.

None is inherently cheap, fair or suitable. Each allocates uncertainty differently.

Compare them using the same fields:

A fixed fee offers little certainty if acceptance is subjective or most integrations sit outside scope. Time billing may be transparent about effort but leaves the quantity uncertain. Usage pricing needs a measurable unit and an alert before spend changes materially. Outcome-linked payment is especially difficult where the agency does not control stock, media, sales handling or market conditions.

Budget the independent gates

Accessibility, privacy, security, intellectual property and legal review are not optional decorations that can be traded away for a lower build quote. They need owners, evidence and money or internal capacity.

The Government Digital Service introduction to making a service accessible tells government teams to budget for accessibility, training and audit work. For public-sector websites, the Public Sector Bodies (Websites and Mobile Applications) (No. 2) Accessibility Regulations 2018, as amended, are relevant.

The regulations state that a website or mobile application of a public-sector body is presumed to conform to the accessibility requirement to the extent that it conforms to WCAG Level A and AA success criteria. Record the legal test in the brief; WCAG 2.2 AA can be an agreed technical or contractual target, but do not assume it replaces the applicable legal requirement. Private-sector duties vary, but leaving design review, manual testing, assistive-technology checks and remediation unfunded creates a predictable gap.

If an audit is commissioned, define the representative templates and journeys. The Service Manual's audit guidance shows why a sample and follow-up route need to be agreed before the test begins.

Privacy work depends on actual processing, and the Information Commissioner's Office says a data protection impact assessment is required for processing likely to result in high risk. Its guidance is under review after legal changes.

Budget a screening decision, evidence collection and any required specialist review. Do not assume an agency's platform label resolves the buyer's controller or processor role.

For security, include threat work, code review, dependency handling, testing, remediation and an incident route. The National Cyber Security Centre's development guidance treats security as continuing work and expressly says its principles do not guarantee a secure product. A one-time launch scan cannot replace maintained controls.

IP also affects cost and exit. The Intellectual Property Office explains that commissioned copyright work is generally first owned by its creator unless the parties agree otherwise in writing. A contract should identify existing and newly created code, designs, copy, fonts, photographs and licences. Payment alone must not be recorded as proof that every right transferred.

Put uncertainty where approvers can see it

A blank model is more honest than a polished total built from invented assumptions. For each uncertain input, record a low, working and high buyer scenario only when there is evidence for those bounds. Note who supplied the range and when it expires.

The budget calculation can remain symbolic:

period cash requirement = approved supplier charges + buyer payroll cash effects + taxes payable + contingency authorised for named risks

full economic cost = period cash requirement excluding recoverable transfers + valued internal time + displaced-resource cost + future operation and exit cost

Do not fill either from an online average. Reconcile supplier invoices to accepted work, and do not mix a VAT-inclusive amount with net entries.

A commercial team can ask a simpler switching question: which input would make the preferred option unaffordable or inferior to repair, defer or do nothing?

Measure value without promising causation

Define success before launch and collect the baseline using the same event rules planned for later reporting. Observed change is not automatically caused by the new site. Campaigns, stock, seasonality, sales practice, measurement loss and other changes may affect the result.

The 2020 Magenta Book explains that impact assessment needs a credible account of what would have happened without the intervention, so separate monitoring from causal evaluation. State what the counterfactual can and cannot support.

A buyer may calculate a project ratio only after a finance and evaluation reviewer agrees the definitions:

project ROI = (attributable contribution minus full economic cost) divided by full economic cost

The numerator, denominator, currency, period, eligible population and exclusions must travel with the result. Run sensitivity checks on contested attribution and cost inputs. Stop reporting the ratio if tracking definitions change, the baseline is not comparable, or the denominator omits material work.

Contract for evidence, change and exit

Turn the cost map into schedules for deliverables, acceptance, charging, licences and data, then add support, changes and exit.

The Cabinet Office Model Services Contract collection suits high-value complex public services, but it is not a standard contract for an ordinary website. An ordinary private buyer can use a signed services agreement with a statement of work and schedules for deliverables, acceptance, charges, IP, data, support and exit; the key is to make those schedules explicit.

Hosting deserves its own record. Government guidance on hosting choices tells public teams to consider operating cost, billing flexibility and the full migration expense. Ask who owns each account, how capacity is measured, what backup and restoration include, and what support is available. Obtain exit estimates before commitment, not after notice is given.

Approval record

No project should pass merely because its headline quote is within budget. Record a separate verdict for service scope, accessibility, privacy and PECR, security, IP and licences, advertising or consumer claims, procurement, commercial terms, VAT and accounting, continuity and exit. A failed legal or safety gate cannot be offset by a favourable price.

The approval pack needs the dated requirement, competing options (repair or defer), a source-backed cost register, quotation assumptions and tax review. Add a sensitivity sheet, acceptance plan, named risk owners and a review date.

Hold if a material unit is undefined, a recurring charge has no term, an essential test has no owner, or correction and exit cannot be funded.

Decision rules before you commit

Common questions

Why is there no standard market rate for a web design agency?

The article states there is no authoritative England-wide tariff for a web design agency. It says a useful budget starts with the service being bought rather than a supposed average price.

What should a buyer record for each cost line?

Record each quantity, billing unit, currency, VAT treatment, term and source date. The article also says to add the buyer's own labour and the cost of operating, changing and eventually leaving the service, and not to enter a number until its basis is known.

How should accessibility and privacy work be funded?

The article says accessibility, privacy, security, intellectual property and legal review need owners, evidence and money or internal capacity. It warns that leaving design review, manual testing, assistive-technology checks and remediation unfunded creates a predictable gap, and privacy work depends on actual processing.