Benchmark Methodology: How We Measure Plugin & Theme Performance

Why We Benchmark

Most WordPress plugin reviews are subjective — they describe features but rarely measure performance. We take a different approach. Every plugin and theme in our plugin performance database is tested in a controlled, isolated environment so you can see exactly how it affects your site’s speed.

This page explains our testing methodology so you know exactly what the numbers on our plugin reviews and theme reviews mean.

Test Environment

  • Hardware: Isolated Docker container with dedicated resources (no shared hosting interference)
  • Software: WordPress 6.8, PHP 8.3, MariaDB 10.11, GeneratePress 3.x theme
  • No caching: No object cache (Redis), no page cache, no CDN — we measure raw WordPress performance
  • Clean install: Single-site WordPress with default content (Hello World post, Sample Page)

This setup mirrors a typical WordPress install without performance optimizations, giving you a true picture of what each plugin adds to your baseline.

What We Measure

TTFB (Time to First Byte)

How long the server takes to begin responding to a request. We measure this via curl against localhost (eliminating network latency). Each measurement takes the median of 5 requests to reduce noise.

Peak Memory Usage

Total memory allocated by PHP during the request, measured via memory_get_peak_usage(true). This tells you how much RAM the plugin adds to every page load on your site.

Database Queries

Total SQL queries executed during the request, measured via WordPress’s get_num_queries(). Plugins that add queries slow down every page load, especially on shared hosting with limited database connections.

How We Calculate Impact (Delta Method)

  1. Measure baseline: Clean WordPress + GeneratePress theme, no extra plugins. Record TTFB, memory, and query count.
  2. Install & activate the plugin under test.
  3. Measure again: Same 3 metrics with the plugin active.
  4. Compute impact: (with plugin) – (baseline) = the plugin’s contribution.

This delta method isolates the plugin’s impact from WordPress core overhead. The baseline captures what WordPress itself costs; the delta is purely what the plugin adds. For example, see our WooCommerce performance review or Contact Form 7 review for real measured data.

We reset the environment every 50 plugins (full database reset + WordPress reinstall) to prevent accumulated state from affecting measurements.

Impact Rating Scale

Rating TTFB Delta Memory Delta Query Delta
Low < 50 ms < 5 MB < 10
Moderate 50–150 ms 5–15 MB 10–30
High > 150 ms > 15 MB > 30

A plugin must meet ALL thresholds for a given rating. If any single metric exceeds the threshold, the higher rating applies. For example, WooCommerce adds +66 database queries, placing it in the High impact category despite modest TTFB. Meanwhile, Akismet adds just +1 query — a Low impact plugin.

Limitations & Caveats

  • These benchmarks measure activation overhead — the cost of having the plugin loaded on every page. They don’t capture all runtime scenarios (e.g., WooCommerce checkout processing or form submission handlers).
  • Real-world performance depends on your server hardware, PHP version, other active plugins, and how you configure the plugin.
  • Some plugins have minimal activation cost but significant per-page cost (e.g., page builders that run on specific pages). Our measurements capture the base load cost only.
  • Results are from a single measurement session. We plan to add periodic re-testing to track changes across plugin updates.

Heuristic Scores vs Measured Data

Every plugin and theme on MakeWPFast receives two types of performance data:

  • Heuristic Speed Score (A–F): Estimated from WordPress.org metadata — update frequency, PHP requirements, user ratings, and feature scope. Available for all items.
  • Measured Performance Data: Real TTFB, memory, and query deltas from our Docker benchmark environment. Available for items we’ve tested.

When measured data is available, it takes priority in our analysis. The heuristic score remains as a quick visual indicator. Items with measured data show a checkmark (✓) next to their score in our plugin archive and theme archive.

Reproducibility

Our Docker Compose configuration and benchmark scripts produce deterministic results. The same plugin tested in the same environment produces the same results within a noise margin of approximately 5 ms TTFB.

We use the median of 5 requests (not the average) to minimize the impact of occasional outlier measurements caused by garbage collection or background processes.

Browse Our Performance Reviews

See the methodology in action — every plugin and theme page shows real benchmark data alongside our heuristic estimates:

Looking for something specific? Start with our most popular reviews: WooCommerce, Yoast SEO, Contact Form 7, Akismet.