Knowing how to fix 404 errors after redesign work is the least glamorous part of a rebuild and the part that protects your traffic. The new site looks better, works better and loads faster. Six weeks later the traffic is down and nobody can explain it.
The explanation is usually mechanical rather than mysterious. The redesign changed the addresses of your pages, every old link now points at nothing, and knowing how to fix 404 errors after a redesign is the difference between a dip and a permanent loss.
Why it happens even on a careful rebuild
URLs change for reasons that all sound sensible at the time. A new theme uses a different permalink structure. Pages get renamed to read better. Services get reorganised into categories. A blog moves from one path to another. Individually each is fine; together they change most of the addresses on the site.
Every one of those old addresses is still out there — in Google’s index, in other people’s links, in email signatures, in a WhatsApp message somebody saved, in your own printed material. They all now lead to a 404.
Find what actually broke
The mistake here is guessing. Three sources give you the real list.
Search Console is the most important, because it shows the addresses Google knows about and is still trying to fetch. Those are the ones with value attached — they were indexed, and some have links pointing at them.
Your analytics from before the redesign. Export the most-visited pages from the six months prior. Every one of those addresses must either still work or redirect somewhere sensible. This is the list that protects your actual traffic.
A crawl of the new site catches internal links that were not updated — menus, buttons and in-content links still pointing at the old structure. Our note on finding broken links on your website covers doing this properly.
Map redirects properly
Redirects after website redesign work are what keep the old addresses alive. A redirect sends both people and search engines from the old address to the new one. Getting the mapping right matters more than getting it done quickly.
- Point each old page at its closest equivalent. The old pricing page goes to the new pricing page, not to the homepage.
- Do not redirect everything to the homepage. It is the most common shortcut and the most damaging one. A visitor arriving from a specific link has to start their search over, and search engines treat a mass redirect to the homepage as effectively a deletion.
- Use permanent redirects for permanent moves. A temporary redirect tells search engines to keep the old address, which is not what you mean.
- Avoid chains. If the page moved twice, point the original address straight at the final destination rather than through the intermediate one.
- Check for loops. A redirect pointing at a page that redirects back produces an error rather than a page.
Keep the old addresses working, or keep the old addresses
There is a choice worth making deliberately at the start, because it changes how much of this work there is.
Keeping the existing URL structure and only changing the design is by far the safer redesign. Nothing breaks, no redirects are needed, and whatever search visibility those addresses have built stays where it is. If the current structure is merely unattractive rather than genuinely confusing, leaving it alone is a defensible decision.
Changing the structure is worth it when the old one is actually a problem — pages buried three levels deep, addresses that say nothing about the page, a blog on a separate domain. If you are going to change it, change it once and map every old address properly. What costs traffic is changing structure casually and mapping it carelessly.
The pages that get forgotten
Every redesign forgets the same things. Images and PDFs — the brochure somebody linked to, the price list in an email. Category and tag pages, which often have links pointing at them. Paginated pages, if the blog structure changed. Anything with a query string, such as a campaign landing page still running in an ad.
That last one is worth checking the same day. An ad pointing at a dead URL is money being spent to send people to an error page.
Then check it stayed fixed
Redirects are not a launch task you finish. Watch Search Console weekly for the first month — new 404s keep appearing as Google re-crawls parts of the old site it had not reached yet.
Keep the redirect rules permanently. There is a recurring temptation to clean them up a year later on the grounds that nobody uses those addresses any more. Somebody does: the old links still exist, and removing the rules breaks them all over again.
Our website redesign checklist covers the rest of the launch, and this is one of the reasons a redesign needs post-launch care rather than being treated as finished on launch day.