How long does a website migration take?

It’s one of the first questions Nicola, our Head of SEO, gets asked when a client is planning to replatform, redesign or move to a new domain: how long does a website migration take? And it is a fair question, because getting the answer wrong in either direction causes real problems. Rush a migration and you risk losing organic traffic that can take months, sometimes years, to recover. Plan without enough runway and the SEO work gets deprioritised, squeezed into the final weeks or skipped entirely.

A properly managed website migration takes a minimum of 12 weeks, and for larger, more complex sites, significantly longer. Here is why, and what needs to happen across each phase.

Why website migrations take longer than most people expect

The most common misconception is that migration timelines are dictated by how long the design or development takes. In practice, that is only one part of the picture.

From an SEO perspective, a migration involves a significant amount of work before a single line of code is written and an equally important period of monitoring and recovery after launch. A study of 892 site migrations found an average recovery time of 523 days from launch to full organic traffic stabilisation, and that is with migrations that were broadly well-executed. Poorly managed ones can result in traffic losses of 30-60% or more, some of which never fully recover.

The preparation work, the redirect mapping, the content auditing, the technical checks, the staging review and the post-launch monitoring are all substantial workstreams in their own right. Compressing them is where migrations go wrong.

The factors that influence how long a website migration takes

No two migrations are identical. The time yours will take depends on several variables.

Size and complexity of the site. A 50-page brochure site and a 50,000-page e-commerce platform are fundamentally different projects. More pages means more content to audit, more URLs to map, more redirects to build and more post-launch monitoring to do.

Type of migration. A straightforward design refresh on the same domain and CMS carries far less SEO risk than a domain change combined with a CMS migration and a URL restructure. The more variables that change simultaneously, the more complex the work and the greater the potential for something to go wrong.

Quality of the existing site. If the site being migrated is already technically healthy, well-structured and has a clean redirect history, there is less remediation work to do. If it carries years of accumulated technical debt, broken links, duplicate content, poor URL structures and inconsistent canonicals, that needs to be resolved as part of the migration, not left to carry over.

Number of teams involved. Migrations that require close coordination between SEO, development, design, content and project management take longer to align. Clear ownership and communication at every stage is essential.

A realistic website migration timeline: 12 weeks minimum

Below is how TAL approaches a migration and why each phase matters.

Weeks 1-3: Audit and discovery

Before anything moves, we need a clear picture of what exists and what it is worth protecting. This means a full technical SEO audit of the existing site, crawling every URL, identifying which pages drive traffic and rankings, mapping the existing URL structure, reviewing redirect chains, checking indexation and understanding the current backlink profile.

This phase also involves a content audit. Which pages should carry across to the new site? Which need updating? Which should be consolidated or retired? These decisions are much harder to make under time pressure, which is why they need to happen at the start, not the end.

Skipping this phase is one of the most common reasons migrations damage organic performance. You cannot protect what you have not first understood.

Weeks 4-6: Migration planning and redirect mapping

With the audit complete, the detailed migration plan is built. This includes a full redirect map, every old URL mapped to its corresponding new URL, as well as an updated sitemap, revised internal linking architecture and any changes to canonical tags or metadata.

For larger sites, redirect mapping alone can be a significant piece of work. Every URL that changes needs a clean 301 redirect in place from day one. Missing redirects mean broken links, lost link equity and a poor experience for users and search engines alike. Google will eventually find the new pages, but the lost authority from broken redirect chains can take a long time to recover.

This phase also involves aligning with the development team on the technical implementation of all SEO requirements, ensuring that the new build will be crawlable, fast, properly structured and that staging environments are correctly locked down to prevent premature indexation.

Weeks 7-10: Staging review and pre-launch testing

Once the new site is built in a staging environment, a thorough pre-launch review is essential. This means crawling the staging site to check that the new URL structure is working as planned, that redirects are correctly implemented, that page titles, meta descriptions and heading structures are in place and that there are no noindex tags or robots.txt directives that could prevent the new site from being indexed after launch.

This is also the point at which page speed, Core Web Vitals and mobile performance should be assessed. Any technical SEO issues identified at this stage are far cheaper to fix before launch than after.

It is common for issues to be identified during staging review that require development time to resolve. Building a buffer into this phase prevents those fixes from pushing the website migration back or being deprioritised.

Week 11: Launch

Launch should be methodical rather than rushed. Redirects go live, the new sitemap is submitted to Google Search Console, the change of address tool is used if the domain has changed and crawl monitoring begins immediately.

For larger sites, a phased launch, migrating sections of the site progressively rather than all at once, can reduce risk and make it easier to isolate and resolve any issues that emerge.

Timing matters too. Launching during a peak trading period, a major campaign or a seasonal spike adds unnecessary risk. Where possible, choose a quieter window.

Weeks 12 and beyond: Post-launch monitoring and recovery

The work does not stop at launch. In many ways, the post-launch phase is where a website migration is won or lost.

In the days and weeks after launch, crawl data, Google Search Console, Google Analytics and rank tracking all need to be monitored closely. Drops in impressions, crawl errors, indexation issues and ranking movements need to be investigated promptly. Some temporary fluctuation is normal, as Google needs time to process the changes, but issues left unaddressed in the early post-launch period can compound quickly.

Technical SEO monitoring should continue for at least three months after launch. For larger sites or those that have made significant structural changes, longer is advisable. Full stabilisation of organic traffic often takes six to twelve months, and in some cases longer.

What happens when website migrations are rushed

The consequences of compressing a migration timeline are well documented. Traffic drops of 30-60% are commonly reported following poorly managed migrations. In the worst cases, sites never fully recover to their pre-migration performance.

The most frequent causes are predictable: incomplete redirect mapping, technical issues carried over from the old site, staging environments accidentally crawled by Google, noindex tags left active at launch and insufficient post-launch monitoring. Almost all of them are avoidable with enough time and the right expertise in the room.

A website migration that takes longer to plan and execute properly is almost always preferable to one that launches quickly and then requires months of remediation.

Planning a migration? Start the SEO conversation early

The single most effective thing you can do to protect your organic performance through a website migration is to involve SEO services expertise from the very beginning, not as a final check before launch. The earlier the SEO workstream is embedded into the project plan, the less likely you are to find yourself making compromises under time pressure.

If you are planning a website migration and want to make sure your organic visibility is protected throughout, get in touch with the team at TAL. We work with businesses at every stage of the migration process, from initial audit and planning through to post-launch monitoring and recovery, and we can help you build a timeline that gives the project the best possible chance of success.

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