The verdict in three sentences
If your WordPress site runs 45 plugins with a mobile PageSpeed score of 38, every month without migrating costs you traffic and leads. A headless migration (WordPress kept as the back office, Next.js on the front end) costs EUR 12,000 to 28,000 excl. VAT in 2026, and a full Next.js + CMS rebuild EUR 20,000 to 45,000, over 6 to 12 weeks. The expected gain is tangible: LCP drops from 4.8 s to 1.6 s and plugin maintenance shrinks.
The real cost of an overloaded WordPress site
A B2B SME WordPress site that has lived 6 or 7 years accumulates extensions: page builder, slider, forms, cache, SEO, security, translation, cookies, pop-ups. At 45 plugins we typically see 3 to 5 update conflicts per year, 1 to 2 critical security alerts and a page weight of 4 to 7 MB. Google measures real user experience through Core Web Vitals: above 2.5 s of LCP, your pages lose rankings to faster competitors.
For an Amsterdam SME selling services or equipment to other businesses, the stakes are direct: half of mobile visitors who wait 5 seconds leave before they see the quote request form.
Headless or full rebuild: which scenario
| Criterion | WordPress optimisation only | Headless migration (WP as back office) | Full Next.js + CMS rebuild |
|---|---|---|---|
| Budget excl. VAT 2026 | EUR 3,000 to 8,000 | EUR 12,000 to 28,000 | EUR 20,000 to 45,000 |
| Timeline | 2 to 4 weeks | 6 to 9 weeks | 8 to 12 weeks |
| Target mobile LCP | 2.8 to 3.5 s | 1.4 to 2 s | 1.2 to 1.8 s |
| Target mobile PageSpeed score | 55 to 70 | 85 to 95 | 90 to 98 |
| Team training | None | None, same back office | 1 to 2 days |
| Exposed plugins remaining | 30 to 45 | 5 to 10, not public | 0 |
| Monthly hosting | EUR 30 to 80 | EUR 40 to 150 (WP + front end) | EUR 20 to 100 |
Headless makes sense if your marketing team publishes often and knows the WordPress editor. A full rebuild is the right call if content needs rewriting anyway or the design is over 5 years old.
Before and after: measured figures
| Metric | Before (WordPress, 45 plugins) | After (headless Next.js) | Change |
|---|---|---|---|
| Mobile LCP | 4.8 s | 1.6 s | minus 67% |
| INP | 340 ms | 110 ms | minus 68% |
| Home page weight | 5.6 MB | 1.1 MB | minus 80% |
| Form conversion rate | 0.9% | 1.6% | plus 78% |
| Premium plugin licences per year | EUR 1,450 | EUR 220 | minus 85% |
| Corrective maintenance hours per year | 40 h | 8 h | minus 80% |
| Annual maintenance cost (at EUR 75 per hour) | EUR 3,000 | EUR 600 | minus EUR 2,400 |
These are 2026 orders of magnitude observed on B2B brochure site migrations of 30 to 150 pages. Conversion gains also depend on page quality, not just speed.
Steps for a clean migration
- Audit: inventory of URLs, plugins actually used, forms and CRM integrations (2 to 4 days).
- Content modelling: page types, custom fields, taxonomies.
- Next.js build: static or incremental rendering, AVIF images, self-hosted fonts.
- 301 redirect plan: every old URL points to its new address to keep existing rankings.
- QA and cutover: real-device mobile testing, Search Console monitoring for 8 weeks.
Mini case study
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Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Sanne, marketing manager at a 35-person Amsterdam SME that installs commercial refrigeration for institutional catering, ran a 90-page WordPress site with 45 plugins. The headless migration took 8 weeks for EUR 19,500 excl. VAT, with hosting at EUR 60 per month.
Before: 1,200 monthly visits, 0.9% conversion, about 11 quote requests per month. After 4 months: 1,450 visits thanks to better rankings, 1.6% conversion, 23 requests. With a 20% close rate and an average gross margin of EUR 4,000 per installation, the 12 extra requests bring about EUR 9,600 of margin per month. The migration pays back in two and a half months, not counting the EUR 2,400 saved each year on maintenance.
FAQ
How much does a WordPress to Next.js migration cost in 2026?
EUR 12,000 to 28,000 excl. VAT for a headless migration that keeps WordPress as the back office, and EUR 20,000 to 45,000 for a full rebuild with a new CMS.
Will we lose rankings during the migration?
Not if the 301 redirect plan is exhaustive. A 5 to 10% dip for 2 to 4 weeks is sometimes seen, followed by growth thanks to better performance.
Will our team need to learn a new tool?
Not with headless: they keep publishing in WordPress. With a full rebuild, 1 to 2 days of training is enough for a CMS such as Sanity or Strapi.
What hosting does a Next.js site need?
EUR 20 to 150 per month depending on traffic, on Vercel, Netlify or an EU server. With headless, add WordPress hosting, often EUR 20 to 50 per month.
How quickly does the migration pay back?
For a B2B SME generating at least 10 quote requests a month, payback usually falls between 3 and 9 months.
Let's scope your project. Send us your site URL and plugin list: we will propose a headless or full rebuild scenario between EUR 12,000 and 45,000 excl. VAT, delivered in 6 to 12 weeks. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
