Website Maintenance Retainer: Annual Cost Benchmark (2026)

The verdict in three sentences

A B2B site is not a frozen asset: without maintenance, it degrades in security, performance and rankings from the first year. In 2026, budget 1,200-4,000 EUR/year for corrective maintenance and security updates, plus 50-90 EUR/hr or a 300-1,500 EUR/month retainer for evolutive work. The most reliable budgeting rule: 15-20% of build cost per year.

Breaking down the 2026 maintenance budget

Maintenance covers three distinct realities that must be priced separately to avoid nasty surprises.

For a premium brochure site built at 15,000 EUR, the 15-20% rule gives an annual envelope of 2,250-3,000 EUR, consistent with serious corrective maintenance plus a small evolution reserve.

Retainer or time-and-materials: how to decide

The choice between retainer and T&M depends on your evolution pace and your need for budget predictability.

Most B2B SMEs choose a modest monthly retainer (maintenance + a small hours pool) and switch to T&M for larger projects (new section, integration, partial redesign).

Mini case study

Mark, digital lead at a mid-cap manufacturer, had a site delivered at 18,000 EUR with no maintenance planned. Eight months later, a flaw in an un-updated plugin causes a breach and 3 days of downtime, with an emergency remediation cost of 4,500 EUR and an estimated loss of 12 lead opportunities. He then signs a maintenance + security retainer at 450 EUR/month (5,400 EUR/year, ~30% of build given the criticality), including monitoring, backups and a 4-hour recovery SLA. Since then: zero major incident, and a smooth, predictable budget.

FAQ

How much does B2B site maintenance cost in 2026?

Between 1,200 and 4,000 EUR/year for corrective and security work, excluding hosting (350-1,500 EUR/year) and evolutive work. The 15-20% of build rule gives a solid starting estimate.

What is the difference between corrective maintenance and evolutive work?

Corrective maintenance repairs and secures the existing site (fixes, updates). Evolutive work adds features and grows the site, billed hourly (50-90 EUR) or via retainer (300-1,500 EUR/mo).

Is a retainer better than hourly billing?

A retainer offers predictability and responsiveness (SLA) for a steady flow of small changes. T&M remains better for a one-off large project where the envelope is hard to scope in advance.

What does a good maintenance SLA cover?

A guaranteed recovery time (often 4-24h by criticality), supervision, regular backups and a priority contact channel. An enhanced SLA adds 20-50% to the base retainer.

Can we skip maintenance to save money?

That is the most common false economy. An unpatched flaw, an obsolete plugin or a missing backup cost far more in emergency remediation than the annual retainer avoided.

Let's scope your project. Share your site's cost and tech stack, your evolution needs and your SLA requirements, and we will propose a retainer (300-1,500 EUR/mo) or T&M (50-90 EUR/hr) sized to your criticality. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.