Hosting for Agencies: 40 Client Sites Without 40 Invoices
Agency hosting gets sold on speed benchmarks. The two things that actually determine whether it works are cost per site and blast radius — and they pull in opposite directions.
Cost per site, three ways
| Sites | Per-site managed | One server, subdivided | Self-run VPS + panel |
|---|---|---|---|
| 5 | $23.00 | $2.20 | $4.20 |
| 20 | $17.00 | $4.40 | $1.90 |
| 50 | $13.50 | $3.52 | $1.52 |
At twenty sites that’s $17.00 per site against $1.90 — nearly nine times. Across forty clients it’s the difference between a $680 monthly hosting bill and a $76 one.
Against what an agency typically bills for hosting and maintenance, the margin picture at twenty sites:
| Billing per site | Managed | Subdivided | Self-run |
|---|---|---|---|
| $30/mo | $260 | $512 | $562 |
| $50/mo | $660 | $912 | $962 |
So on pure unit economics, subdividing wins and self-running wins slightly more. That’s not the recommendation, and the reason is the next section.
Blast radius, which is what you’re actually buying
This is the part that burns agencies, and it’s architectural rather than a benchmark.
On one server subdivided across twenty sites, resources are shared. When one client installs a plugin that pins the CPU, runs an unbounded query, or gets hit by a scraper, the other nineteen sites slow down. You then get nineteen emails about a problem caused by one client, and you cannot bill any of them for it.
On per-site managed hosting, each site has its own resource allocation. The same runaway plugin degrades that client’s site and nobody else’s. That’s what the 9× premium buys — not speed, isolation.
On a self-run VPS it’s the same shared-resource problem as Cloudways, plus it’s unambiguously your fault. With a managed host you can say “the host is investigating.” With your own box, you are the host.
The rule that follows: the cheaper architectures are correct until one client’s behaviour can cost you a different client. That threshold isn’t a site count — it’s a client-quality question.
- Sites you built, maintain and control the plugin list on → subdividing is fine
- Sites where clients have admin access and install what they like → isolate them, or accept that you’re one plugin away from a bad week
Mixing both on one server is the worst of it. If you must subdivide, keep client-managed sites off the server your controlled sites live on.
The operational things that cost more than hosting
Four items agencies forget when comparing plan prices.
Migrations. Onboarding twenty sites is twenty migrations. Hostinger’s unlimited free migrations and SiteGround’s migrator plugin materially change onboarding cost; GreenGeeks includes one free on shared and charges $15 per additional site, which is $285 across twenty.
Staging seats and environments. Real branch-based staging on every site is an agency workflow requirement, not a nicety, and it’s priced very differently across these platforms.
Client billing. Either you invoice and reconcile manually, or the host provides sub-accounts and billing you can hand over. This is where white-label reseller products earn their keep.
Support hours — the biggest one. At twenty sites, one hour a week of client hosting questions is 52 hours a year. If a host’s support is good enough that clients’ problems get solved without you, that’s worth more than the plan difference, which is the argument for managed that unit economics can’t see.
And the question nobody asks until 2am: when a client site goes down at 2am, who is contractually obliged to be awake? On managed hosting, the host. On your VPS, you. Price that honestly against a $600/month saving.
The headcount rule
Roughly, and it tracks who absorbs failures rather than how many sites you have:
Solo, up to ~10 sites you fully control → one subdivided server. You can fix anything yourself, the blast radius is your own work, and the economics are unarguable.
Small team, 10–40 sites, mixed control → per-site managed for client-admin sites, one subdivided server for the ones you control. The hybrid is more work to explain and cheaper than isolating everything.
Any size, clients with SLAs → per-site managed, and stop optimising the hosting line. The premium is insurance against a failure mode that costs client relationships rather than dollars.
No dedicated ops person, more than ~20 sites → managed. If nobody’s job is infrastructure, self-running is a liability that surfaces on the worst possible day.
The hosts
Cloudways is the subdivided-server answer and the best unit economics with real tooling — you rent a defined server, host many sites on it, get staging, and pay monthly with no term. $11/month for 2GB, $88 for 8GB. Understand that resources are shared across the sites you put on it.
Kinsta is the per-site managed pick, with genuine agency tooling — multi-site dashboard, environments, and client billing that people stay for despite the arithmetic. Its overage is $0.50 per 1,000 visits, the gentlest in managed WordPress, and bandwidth-based plans exist since November 2025 if bot traffic inflates client counts.
WP Engine is the other agency-shaped platform, strong on transferable installs — handing a finished site to a client’s own account is a workflow feature, not a nicety. Its overage is $2.00 per 1,000 visits, four times Kinsta’s, which matters across a portfolio.
Rocket.net doesn’t meter visits at all, from $30/month per site, billing disk and bandwidth instead. For an agency with unpredictable client traffic, not being metered removes a category of client conversation you don’t want to have.
Flywheel is built around designer and agency workflows specifically — and is owned by WP Engine, so it’s a product choice rather than a different supplier.
Nexcess and Liquid Web sit at the managed and fully-managed ends. Liquid Web is the answer when “who takes the 2am call” needs a contractual answer.
ScalaHosting runs its own SPanel rather than licensing cPanel and includes it — genuinely relevant to reseller margins, since a per-account panel licence comes straight out of your per-site economics.
GreenGeeks offers white-label reseller hosting with cPanel/WHM and WHMCS billing. Price the migrations: one free, then $15 per site.
For the reselling-versus-managing decision underneath all of this, we modelled it at ten clients — and the finding was that charging a retainer beats marking up hosting by a wide margin.
How we checked this
Plan pricing is each provider’s published figures read in August 2026 across this series: Kinsta’s multi-site tiers at $115 for WP 5, $340 for WP 20 and $675 for Agency 60, its $0.50 per 1,000 visit overage; WP Engine’s $2.00 per 1,000 overage; Cloudways at $11 for 2GB and $88 for 8GB; Rocket.net from $30; Hostinger’s 16GB tier at $28.99; and GreenGeeks’ one-free-then-$15 migration terms.
The cost-per-site table is our arithmetic and it embeds one big assumption: that a given server comfortably hosts a given number of sites. We’ve assumed roughly twenty small WordPress sites on an 8GB server and control-panel costs of about $9/month per server. We have not tested that density. How many sites fit depends entirely on their traffic, plugins and caching — a single busy WooCommerce store can consume what twenty brochure sites would, which is precisely the blast-radius problem the article is about. Treat the per-site figures as illustrative of the shape rather than as a capacity planning guide.
The billing figures of $30–75 per site per month are illustrative of what agencies charge, not surveyed data.
On blast radius: that shared server resources mean one site’s consumption affects others is a property of the architecture, not a measurement. We haven’t instrumented a shared server to quantify how much one runaway process degrades its neighbours — and that magnitude would vary too much to generalise anyway. The claim is directional and it’s the reason the article doesn’t simply recommend the cheapest option.
What we did not verify: agency-specific tooling in practice — multi-site dashboards, sub-account permissions, client billing handover and transferable installs are described from how each provider positions itself rather than from accounts we hold and used. That’s the half of this decision we’d least want treated as a verdict, and it’s the half that keeps agencies on platforms the arithmetic says they should leave.
The host links above are affiliate links. The cheapest architecture in this article — one server subdivided — points at the lowest-priced products we list.
FAQ
How much should agency hosting cost per site?
Between about $1.50 and $23 depending on architecture. Per-site managed runs $13–23, one subdivided server $2–4, and a self-run VPS with a control panel around $1.50–4.
Is it cheaper to put all client sites on one server?
Much — roughly nine times cheaper per site than per-site managed hosting at twenty sites. The cost is shared resources: one client’s runaway plugin slows every site on that server.
When should an agency use per-site managed hosting?
When clients have admin access and install their own plugins, when any client has an SLA, or when nobody on your team owns infrastructure. You’re buying isolation and someone else’s on-call rota.
What do agencies forget when comparing hosting costs?
Migrations at onboarding, staging environments, client billing, and support hours. One hour a week of client hosting questions across twenty sites is 52 hours a year.
Which host is best for agency client billing?
Kinsta and WP Engine have the most developed agency tooling and client handover. For white-label reselling with your own branding, InMotion and GreenGeeks provide cPanel/WHM with WHMCS billing.
Should I resell hosting or charge a management retainer?
Charge a retainer. Reselling at ten clients nets a fraction of what a $50 retainer does at the same support load, and it makes you the hosting company permanently.
How many WordPress sites fit on one server?
It depends entirely on their traffic and plugins — one busy store can consume what twenty brochure sites would. That variability is why shared-server architectures carry blast-radius risk rather than a fixed capacity number.
