- Start by classifying your migration. If the website has little SEO substance, the potential is high. If it is well optimized, the main job is to hold your ground.
- Use data from the last 12 to 18 months to calculate three scenarios: status quo, growth and a migration without SEO.
- The gap between the status quo and the worst case is the value SEO protects in the project. Measure budget and effort against it.
- Show the numbers early to everyone involved in the migration, especially management.
How much SEO risk does your migration carry?
A relaunch usually aims to improve usability, conversion, branding or page speed and, in the end, to bring in more revenue. SEO often joins the planning too late. If you are involved in the planning, you need good arguments early on. You find them by assessing the risk and potential of the migration for your company.
From an SEO perspective, there are three types of relaunches.
| Type | Starting point | SEO's job in the project |
|---|---|---|
| Low risk, high potential | The website is hardly search-engine-friendly yet and has little to lose from an SEO perspective. | Set up technology, structure and content correctly in the relaunch. If SEO is properly integrated, organic performance will very likely improve significantly. |
| Medium risk, medium potential | The website has already been optimized, has some SEO success and still has room to grow. | A relaunch without SEO can destroy the work of previous years. With current SEO know-how in the project, performance can still grow after the relaunch. |
| High risk, low potential | The website is state of the art in technology and content and can hardly be improved. | Secure the status quo and do everything to make sure the relaunch costs no traffic or revenue. |
This assessment does not require an in-depth analysis. A quick look at the optimization status and the development over the last few years is enough.
One basic requirement applies to all three types. The new website must be crawlable and indexable for search engines. Google also recommends planning the changes of a site move one after the other. The more changes at once, such as domain, URLs, templates and CMS, the higher the risk.
Which SEO goals fit your migration?
Derive concrete goals from your assessment.
- Low risk, high potential. The goal is a significant increase in organic traffic and the revenue it generates. In concrete terms, that could mean catching up with a competitor that already performs well in SEO, or leading the organic search results for a topic.
- Medium risk, medium potential. The minimum goal is to preserve current SEO performance. Beyond that, you seize the chance to gain more traffic. Anyone who has invested in SEO before usually has a list of recommendations that were never implemented. They belong in the relaunch project, together with further measures.
- High risk, low potential. All SEO resources work toward preserving current performance and preventing losses from the relaunch. If capacity is left over, you can review tactics, strategies and processes for the new website.
What data do you need for the forecast?
A solid forecast starts with a look back. Ideally, your web analytics provides revenue attributed to organic traffic. If it does not, calculate with clicks or sessions from organic search. In that case, it is worth setting up your analytics so you can tie SEO measures to revenue in the future.
| Source | What you get | What to watch for |
|---|---|---|
| Google Search Console, Performance report | Clicks and impressions from Google Search per page and query | The data goes back 16 months. For longer series, save it regularly or use the BigQuery export. |
| Web analytics, e.g. Google Analytics | Sessions, conversions and revenue from organic search per landing page | Standard reports are not affected by data retention. Explorations are limited to 2 or 14 months. |
| Your own revenue figures | Revenue per category or page type | Helpful when web analytics does not attribute organic search revenue cleanly. |
Look at the development over the last 12 to 18 months. That shows you the trend and seasonality. If you split the data by page type, such as categories, products and guides, you see where the migration touches the most revenue. How to keep your Search Console data permanently is explained in the guide Search Console BigQuery export.
How do you calculate the three scenarios?
- Preserve the status quo. If the migration is meant to secure the current level, simply continue last year's development after go-live.
- Growth. Depending on the potential from your assessment, plan for a slight or significant increase after the migration.
- Migration without SEO. For comparison, calculate the worst case. The migration ignores SEO and costs a lot of organic traffic and revenue.
| Scenario | Revenue in the 12 months after go-live | Gap to status quo |
|---|---|---|
| Preserve status quo | €2,640,000 | – |
| Growth | €2,748,000 | +€108,000 |
| Migration without SEO | €2,130,000 | −€510,000 |
How deep the drop goes in the worst case depends on your website. State your assumption openly and justify it, for example with earlier migrations in your own company. Google itself writes that rankings can fluctuate during a site move. For medium-sized websites, it can take a few weeks or more until Google shows the new URLs, and even longer for large sites.
How much may SEO cost in a migration?
If you work with revenue instead of traffic, you can even calculate an ROI for the SEO part of the migration. The gap between the worst case and the status quo has real value for your company. Ask yourself what budget and staff it takes to reach that goal and whether the math works out. The same applies to the growth scenario.
In the example, the gap between the worst case and the status quo is €510,000 over twelve months. An SEO project that costs well below that is easy to justify. Between status quo and growth there is another €108,000. If the additional budget for that goal stays below this amount, approval should be possible.
Also plan for the weeks after go-live. During that time you need SEO and IT capacity to fix errors quickly.
Who do you need to convince with the numbers?
Depending on your role and the structure of your company, these people belong at the table.
- Project or program management of the migration
- IT
- Management
- Marketing
- External contractors, agencies and consultants
- Design and development
- Editorial and content management
With the numbers and the chart you show them that SEO is crucial for the success of the entire migration and needs budget and time. If everyone, especially management, commits to the SEO goals early on, chances are good that the migration will succeed from an SEO perspective.
How do you check the forecast after go-live?
The forecast stays useful after go-live. Compare actual clicks with the three scenarios week by week, ideally per page type. If an area falls well below the status quo, look for causes there first. The typical causes are described in the guide SEO risks in a website migration. Which pages you should not lose in the first place is covered in Important content in a website migration.
What to check before and after go-live is listed in the website migration checklist, the SEO check before go-live and the guide to testing redirects.
How accurate is a traffic forecast for a website migration?
It is a range with openly stated assumptions. Its value lies in comparing the scenarios. That comparison shows how much is at stake and what SEO protects in the project.
Are clicks enough for the forecast, or do I need revenue?
Clicks are enough. With clicks from Search Console you show how much visibility is at stake. With revenue you can also calculate an ROI for the SEO work.
How far back should the data go?
12 to 18 months, so trend and seasonality become visible. Search Console shows 16 months. If you want to look further back, save the data in advance, for example with the BigQuery export.
How long does it take for traffic to settle after a migration?
For medium-sized websites, Google mentions a few weeks or more until the new URLs appear in search. Large websites take longer. Errors in redirects or content extend this phase considerably.
Sources
Retrieved on November 3, 2026. If something is out of date or missing, let us know.
- Google Search Central, Site moves with URL changes: https://developers.google.com/search/docs/crawling-indexing/site-move-with-url-changes · August 20, 2026
- Google Search Central Blog, Introducing the new Search Console (16 months of data): https://developers.google.com/search/blog/2018/01/introducing-new-search-console · January 8, 2018
- Search Console Help, Performance report (Search results): https://support.google.com/webmasters/answer/7576553?hl=en
- Google Analytics Help, Data retention: https://support.google.com/analytics/answer/7667196?hl=en