Upfront: migrating from WordPress to a headless CMS architecture with Next.js is not a small project. Depending on site size and custom functionality, expect £8,000–£40,000 / $10,000–$50,000 and six weeks to six months. Whether that's worth it depends on why you're migrating—and most teams skip that question.
Quick cost table (2026)
| Project size | Typical range | Timeline |
|---|---|---|
| Small (up to 20 pages) | £8,000–£15,000 / $10,000–$18,000 | 6–10 weeks |
| Medium (20–100 pages) | £15,000–£30,000 / $18,000–$38,000 | 10–16 weeks |
| Large/complex (100+ pages, heavy integrations) | £30,000–£60,000+ / $38,000–$75,000+ | 4–6+ months |
Use this as a planning range, not a fixed quote. Final price moves with content cleanup, SEO redirect scope, and WooCommerce/custom integration complexity.
For how the stack fits together — architecture, API choice, and setup — see our headless WordPress with Next.js guide (includes an architecture diagram and 2026 best practices).
This guide covers cost drivers, realistic timelines, and where WordPress → headless CMS migrations fail. Numbers come from client projects we deliver worldwide—not generic agency ranges. For stack context, see React vs WordPress for business websites.
First: is WordPress to headless CMS migration actually necessary?
No—migrating WordPress to Next.js or a new headless CMS is not automatically necessary.
The situations where a migration genuinely makes sense: your mobile PageSpeed scores are in the 30s and the theme vendor has given up on fixing it—though it's worth running through Core Web Vitals fixes on WordPress before you pay for a rebuild. Your marketing team wants landing pages and the current setup makes every new page a small crisis. You're running plugins that conflict with each other and your developer's solution is always "just add another plugin." You're expanding internationally and need proper multilingual routing that WP Multilite can't actually handle at scale.
If none of those sound familiar, a migration might not be the right project. A comparison of the two stacks is worth reading before you commit to anything.
What you're actually migrating
People say "migrate our WordPress site".
Content is usually the most tedious part. If your WordPress site has been running for five years and has 300 posts, someone has to move all of that to the new CMS—whether that's Sanity, Contentful, or WordPress itself staying in place as a headless backend. Automated migration scripts help but they never get everything right. Budget time for cleanup.
Design gets rebuilt from scratch in React components. This is actually one of the better parts of the process—you're not inheriting a theme's weird CSS decisions. But it takes time and it needs a designer and a developer working together, not one person doing both badly.
Functionality is where surprises happen. Contact forms are fine. WooCommerce is a full separate conversation. Custom post types with complex relationships, membership plugins, booking systems wired into third-party APIs—each of these needs to be assessed individually. Some are straightforward to rebuild. Some are not.
The CMS question is often the most important one nobody asks early enough. Are your editors staying in WordPress (headless) or moving to a new CMS entirely? Staying in WordPress is less disruption for the team but adds architectural complexity. Moving to a new CMS requires training and data migration on top of everything else.
Cost breakdown by project size
Small site £8,000–£15,000/$10,000–$18,000
20 or less than 20 pages site, not hectic work. You're rebuilding a brochure site and maybe a blog. The main cost here is design and build—getting the components right, hitting performance targets, making sure SEO doesn't fall off a cliff during the transition.
6-10 weeks if all things are ready. Actually this is true that delay in small migrations are from client not from agency due to late approval.
Medium site £15,000–£30,000/$18,000–$38,000
This is for the sites which have more content to manage, multiusers and integrations. B2B businesses, education platforms, service companies with several locations—this is where most migrations actually land.
Ten to sixteen weeks. Content migration and CMS configuration eat more time than most clients expect. The development itself is rarely what extends the timeline.
Large or complex site £30,000–£60,000+/$38,000–$75,000+
Four to six months minimum. Sometimes longer. If an agency quotes you eight weeks for a WooCommerce migration with 5,000 products and twelve payment methods, ask them to show you a similar project they've done before.
The risks people don't ask about
SEO during the transition. This one causes real damage when it's handled poorly. URL structures change, redirect maps get incomplete, internal links point to 404s, structured data breaks. We've seen businesses lose 40% of their organic traffic in the month after a migration because nobody owned the SEO handover.
Content that was never actually managed properly. WordPress's flexibility means a lot of teams have content living in weird places—custom fields with no documentation, page builders with proprietary shortcodes that don't export cleanly, images embedded in post content with hardcoded URLs. None of this surfaces in a demo. It all surfaces when you start migrating.
The CMS learning curve. If your editors have been in WordPress for three years and you move them to Contentful, expect friction. Not because Contentful is hard, but because any change to a workflow people do fifty times a week takes adjustment. Factor in training time and a period where both systems run in parallel.
Performance assumptions. Just because you're on Next.js doesn't mean the site will be fast. We've audited Next.js sites scoring worse than the WordPress they replaced because nobody thought about image optimisation, JavaScript bundle size, or rendering strategy. The framework gives you the tools. Someone still has to use them correctly. If you're still on WordPress, see how to fix Core Web Vitals before assuming migration is the only path.
What a well-run migration looks like
Discovery comes first—not a proposal, not a quote, a proper look at what you have. How many pages, what functionality, what the content model looks like, where the third-party integrations are, what the CMS workflow needs to support. An agency that quotes a WordPress migration without doing this is guessing.
Then a redirect map before build starts, not after. Then design and build in parallel where possible. Then a staging environment where the client can review before anything goes live.
Working on Performance asked before the Project starts. Not "we'll aim for good scores"—actual numbers. For reference, the Oxbridge Summer Courses site we built hit mobile Core Web Vitals passed with LCP 1.8s and CLS 0.01. That was the target going in, not a happy accident at the end.
Headless WordPress vs full headless CMS migration
Many businesses assume migration means abandoning WordPress entirely. Headless WordPress keeps editors in the admin they know: WordPress stays the CMS, Next.js serves the public site. You get performance, SEO control, and modern front-end flexibility without retraining the whole content team.
A full headless CMS move (Sanity, Contentful, etc.) makes sense when WordPress itself is the bottleneck—plugin sprawl, broken custom fields, or licensing pain. Higher migration cost, cleaner long-term model. We map which path fits in discovery before quoting.
FAQs: WordPress to headless CMS migration
How much does WordPress to Next.js migration cost in 2026?
Most business migrations land at £8,000–£40,000 / $10,000–$50,000 depending on site size and integrations. Small sites (up to 20 pages): £8,000–£15,000 / $10,000–$18,000, typically 6–10 weeks. Medium sites (20–100 pages): £15,000–£30,000 / $18,000–$38,000, 10–16 weeks. Large or complex builds (100+ pages, WooCommerce, heavy custom logic): £30,000–£60,000+ / $38,000–$75,000+, often 4–6+ months. These are planning ranges from real agency projects—not fixed quotes.
How long does a WordPress to headless CMS migration take?
About 6 weeks for a small brochure site with clear content, up to 6 months for a large platform with e-commerce or complex integrations.
What happens to my SEO rankings after migrating?
They can, if the migration is handled carelessly. A proper redirect map, pre-launch SEO audit, and monitoring setup in place before go-live will prevent most of the damage. Rankings sometimes dip slightly during the transition period regardless—Google needs time to recrawl. A well-executed migration recovers within weeks. A badly managed one can take months.
Do I have to leave WordPress completely?
No. With headless WordPress, editors stay in the admin; visitors get the fast Next.js front end.
Can I migrate WooCommerce to Next.js?
Yes, but it will be a bigger Project. Payment flows, product data, inventory, orders—all of it needs careful rebuilding. Get a proper scoping session before anyone quotes you a number for this.
How does migration cost vary by region or agency?
Agencies in major markets (e.g. London, New York, Sydney, Dubai) often sit at the top of the ranges above. Regional and specialist studios can come in lower. What matters more than location is what's actually in scope—two quotes at the same price can represent very different amounts of work.
Related resources
- WordPress migration services
- Headless WordPress & Next.js
- Fix Core Web Vitals in WordPress
- React vs WordPress: full comparison
- Why hire a Next.js developer
- How to choose a web agency
- Oxbridge Summer Courses case study
Bottom line
A WordPress to Next.js migration done properly will improve your performance, your SEO control, and how much your team can do without filing a dev ticket. Done carelessly, it'll cost you rankings, editorial workflow, and more money to fix than the migration cost in the first place.
The difference is almost always in how much was scoped and agreed before the project started—not what framework ended up in the repo.
We run these migrations for clients worldwide. Services · Book a consultation.
