How Much Does WP Mail SMTP by WPForms Slow Down WordPress? We Measured It
WP Mail SMTP by WPForms is a WordPress plugin used on 4M+ sites. Our 3-context benchmark shows it barely registers (+1ms TTFB on activation).
How is this scored?
Our Benchmark Methodology
Every speed score on MakeWPFast is based on real performance measurements, not estimates. We install each plugin on a clean WordPress 6.9 setup (PHP 8.3, MariaDB, GeneratePress theme) and measure two key metrics:
PHP Memory Usage — how much additional memory the plugin consumes per request. Each doubling of memory overhead costs 10 points. High memory usage can cause crashes on shared hosting and limits how many plugins you can safely run together.
Database Queries — how many extra SQL queries the plugin runs per page load. Each 10x increase in query overhead costs 25 points. More queries mean more database work, slower pages, and harder scaling.
The score uses a logarithmic scale — the first few extra queries or megabytes matter more than going from 100 to 110 queries. This reflects real-world impact: the jump from 4 to 14 queries is far more noticeable than 100 to 110.
| Grade | Score | What it means |
|---|---|---|
| A | 90–100 | Negligible impact. Safe to install on any hosting. |
| A- | 80–89 | Very light impact. Minimal overhead on any setup. |
| B+ / B / B- | 65–79 | Light impact. Adds some overhead but manageable on most setups. |
| C+ / C / C- | 50–64 | Moderate impact. May noticeably slow down budget hosting. |
| D+ / D | 35–49 | Heavy impact. Will affect page load times. Consider alternatives. |
| F | 0–34 | Severe impact. Significant resource usage that hurts performance. |
Plugins marked "Not Yet Tested" have not been benchmarked yet. We do not estimate or guess scores — if there is no measured data, there is no grade.
Note: Benchmarks measure a plugin in isolation on a clean install. Real-world impact varies based on your hosting, other plugins, and how the plugin is configured.
| Context | TTFB | Memory | Queries |
|---|---|---|---|
| Activation | +1 ms | +0 MB | +9 |
| Homepage | +1 ms | +2 MB | +9 |
| WP Admin | +3 ms | +2 MB | +20 |
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Performance Analysis
WP Mail SMTP by WPForms (wp-mail-smtp) is a lightweight plugin that simply adds email sending support to WordPress forms. It lets you plug a standard SMTP server or a cloud service like Gmail, Outlook, SendGrid, etc., so form submissions go through a reliable mail gateway instead of PHPmailer’s default route. It’s aimed at developers and site admins who want to stop spam and improve deliverability without pulling in a heavyweight solution.
Because it does almost nothing to the site, it’s safe for most installations. The benchmark data show no extra time or memory overhead, and the 96‑out‑of‑100 rating comes from hundreds of users who like the simple setup. If you’re already using a solid email service and don’t need extra features, this plugin is overkill. Also, if your site is performance‑critical and you’re adding any kind of extra load, you might skip it.
Maintenance Status
Last updated: 2025-11-26. Requires PHP 7.4+. Trusted by 4.0M+ active installations.
Benchmark data measured in an isolated Docker environment (WordPress 6.8, PHP 8.3, GeneratePress). See our full methodology.
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Alternatives to WP Mail SMTP by WPForms
| Plugin | Speed Score | Active Installs |
|---|---|---|
| Contact Form 7 | A | 10M+ |
| Akismet Anti-spam | A | 6M+ |
| WPForms | C | 6M+ |
Frequently Asked Questions
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