“How much RAM does a small business website need?” is the single most common sizing question we see, and the honest answer is a range, not a number. This article gives you the measured figures behind that range so you can size with data instead of guessing.
What actually consumes memory on a web server
On a typical LAMP or LEMP stack, resident memory is consumed by four things: the operating system and base services, the web server process, the application runtime (PHP-FPM workers for most small business sites), and the database. Each has a floor, and each scales differently with traffic.
| Component | Idle RAM | Under moderate load |
|---|---|---|
| OS + systemd + sshd | 120–200 MB | same |
| Nginx | 20–60 MB | 60–150 MB |
| PHP-FPM (per worker) | 40–90 MB | same per worker |
| MariaDB/MySQL | 250–500 MB | 500 MB–1 GB |
| Redis (object cache) | 0 (optional) | 80–200 MB |
A single cached WordPress site with two PHP-FPM workers and a lean database sits comfortably around 600–900 MB resident. A business site with a contact form, a small product catalogue, and a booking plugin sits closer to 1.2–1.6 GB.
Sizing by site type
- Brochure site (5–10 pages, no cart): 1 GB is sufficient; 512 MB works with aggressive caching.
- Business site with dynamic forms and plugins: 2 GB is the comfortable floor.
- Small WooCommerce store (under 500 products): 2–4 GB, plus Redis if you can.
- Multi-site or agency server (5+ client sites): 4–8 GB, isolated per-site in PHP-FPM pools.
The jump from 1 GB to 2 GB is the most cost-effective upgrade a small business site can make, because it eliminates swap-thrashing during traffic spikes and plugin-heavy admin sessions.
Traffic matters less than concurrency
Monthly visitor counts are a poor sizing metric. What matters is how many requests are in flight at the same instant. A site with 50,000 monthly visitors that receives them evenly needs far less RAM than a site with 5,000 visitors that all arrive in a ten-minute burst. Estimate your peak concurrent requests, multiply by the average memory per PHP worker, and add the database floor. That is your true requirement.
Why swap is not a substitute for RAM
When a server runs out of physical memory, the kernel moves cold pages to swap on disk. On a budget VPS with shared NVMe or, worse, network-backed storage, swap latency is measured in milliseconds rather than nanoseconds. A site that swaps during peak traffic does not slow down gracefully — it stalls. The first request that triggers a swap-in can block for hundreds of milliseconds, and under concurrent load those stalls compound. Swap is a safety net for unexpected spikes, not a capacity plan.
The role of caching in reducing RAM pressure
Object caching is the cheapest memory upgrade you can buy, because it converts repeated database queries into memory lookups. A Redis instance using 100–150 MB can cut the database’s working set and reduce PHP execution time enough to serve noticeably more traffic on the same plan. Page caching at the Nginx or CDN layer goes further still, because a cached page never touches PHP-FPM or the database at all.
- Page cache (Nginx fastcgi_cache or a CDN): largest reduction in resource use per dollar. Zero cost on most stacks.
- Object cache (Redis): 100–200 MB buys a large reduction in database load.
- Opcode cache (OPcache): built into PHP; enable it and give it 64–128 MB.
- Full-page static export: for purely informational sites, removes the application from the request path entirely.
A practical sizing procedure
- Install a monitoring tool and record resident memory over a full week, including your busiest hour.
- Identify your peak, not your average. Size to peak plus 30%.
- Confirm the plan offers dedicated (not burstable) memory at that size.
- Verify the storage and transfer allowance covers your traffic, not just your memory.
- Budget for the year-two renewal price, not the introductory rate.
If your measured peak with margin lands at 1.3 GB, buy 2 GB, not 1 GB. There is no upside to running a production business site at 90% memory utilization. Compare current plans and their year-two pricing on the budget VPS comparison table before you decide.
Related reading on this blog: RAM headroom guidance, swap vs more RAM, and how much RAM a $5 plan actually provides for WordPress.
