When to compare technical SEO pricing models for your budget

What to take away

How do retainer and project models differ in practice?

A retainer buys capacity. You pay for a set number of days or hours each month, and the supplier decides how to spend them across crawling, log analysis, Core Web Vitals work and reporting. It suits sites with continuous releases, because regressions appear weekly rather than annually.

A fixed-price project buys a defined output: a migration plan, a site audit, a structured data rollout. Scope is agreed upfront and the fee does not move unless the scope does. This suits teams with a single, time-boxed problem and an internal developer to implement fixes.

Hourly rates sit between the two. They are transparent but unpredictable, and they punish clients whose sites are messier than expected. UK benchmarks help.

Typical UK market ranges are £1,000 to £5,000 a month for retainers, £2,000 to £10,000 for fixed-price projects, and £50 to £150 an hour. Screaming Frog's SEO pricing survey is one published UK benchmark for checking quotes. The technical SEO costs and budget guide for England sets out how to compare them.

Which model fits a migration or a replatform?

Migrations reward fixed-price projects with a written change log. The risk is concentrated in a short window, so you want a supplier who will document redirect maps, canonical rules and rollback steps before go-live. A retainer can work if the contract names the migration as the priority.

If you are weighing suppliers, ask them to price the same migration brief in both formats. The gap between the quotes tells you how much uncertainty they are carrying.

How do outcome-based fees work, and when are they risky?

Outcome-based fees tie payment to a metric: organic sessions, index coverage or revenue from non-brand queries. They need a baseline agreed before work starts, plus a control for seasonality and algorithm updates.

A common structure is a £1,500 monthly base plus 10% of any non-brand session growth above a baseline of 50,000 sessions a month. Risk sits with the supplier, so expect a higher headline rate or a longer minimum term.

The ICO's guide to the Privacy and Electronic Communications Regulations confirms that consent rules sit with the site owner, which limits what any agency can promise.

Extra costs: tax and measurement

Tax, off-payroll status and ad blocking sit outside the core fee. Check HM Revenue & Customs guidance on off-payroll working before agreeing terms. The IAB UK consumer notice guide covers publisher-side ad-blocking expectations. Budget for a measurement review if your traffic mix includes heavy ad-blocking audiences.

Before and after: illustrative monthly budget

The table below is a labelled example for a mid-sized English retailer, and the figures are illustrative rather than quoted. Our companion piece on technical SEO cost guide data and sources explains how to check supplier quotes against published benchmarks.

The after column adds £1,300 a month, or 52%, for work that protects the data the retainer depends on. For a team paying £400 a month for a small audit tool, the same logic applies at a smaller scale.

Common questions

Is a retainer always more expensive than a project?

No. Over twelve months, a project fee can exceed a modest retainer if the site needs repeated fixes. Compare total cost of ownership, not monthly rate.

Can I mix models in one contract?

Yes. A common structure is a small retainer for monitoring plus fixed-price blocks for migrations or audits. Ask for the split in writing.

What should I check before signing an outcome-based deal?

Confirm the baseline, the measurement window and who owns the analytics tag. Low consent rates can make the metric unreliable.

Do I need a separate budget for compliance?

Often yes. Cookie consent, tracking reviews and ad-blocking measurement are distinct tasks with distinct costs, and they affect the numbers your SEO reporting depends on.