Anyone with a few years of experience running a WordPress website is familiar with “load lag,” the gradual degradation of site speed as more and more plugins, images, and scripts are added over time. If you are continuously updating and improving your WordPress site, you will eventually experience it.

Site speed is critical to an engaging visitor experience. Over time, maintaining viable site speed becomes a matter of balancing design needs with user experience needs.

A performance budget is a practical framework for WordPress performance optimization. It sets clear limits for metrics that affect site performance (such as total page size, number of HTTP requests, Core Web Vitals) and can assist with maintaining this design/UX balance. The goal of a WordPress performance budget is to treat performance as a formal constraint during design and development, rather than an afterthought.

This article explores how to establish a WordPress performance budget, identifying which site performance metrics matter most and how to monitor them to ensure your site remains lean and fast.

Determining Your Key Metrics

When developing a WordPress performance budget, what metrics should you focus on?

Timing-Based Milestones

• Largest Contentful Paint (LCP): This metric measures how long it takes for the main, largest content (like a large text box or image) to load and become visible in a visitor’s viewport. LCP indicates how fast a page’s primary content appears.
• First Input Delay (FID): This metric measures the time from a user’s first interaction (like a click or a tap) to the moment the browser starts processing the event. FID reveals how responsive a page feels during loading, especially when heavy Javascript blocks the main thread. (Keep in mind that Google is planning to replace FID with Interaction to Next Paint, or INP, which measures how responsive a page feels when a user interacts with it.)

Quantity-Based Metrics

• Total Javascript Bundle Size: Keep Javascript bundles under 200kb.
• Total Image Weight: Keep image weight under 500kb.
• Total external HTTP requests: Keep HTTP requests ideally under 25 per page load (50 max).

Keep in mind that these quantity-based metrics are general benchmarks and may vary based on purpose and audience. Different web pages require different metrics. For example, a home page will typically load quicker compared to an ecommerce page with lots of images.

When determining your WordPress site’s performance budget, keep in mind the golden rule: A performance budget is most effective when it is 20% faster than your top competitor. This rule helps you determine what you should be aiming for with your own site’s performance budget.

The Loading Waterfall Chart

To determine the current speed performance of your WordPress site, conduct a performance audit using a tool like Webpagetest, Pingdom, or GTMetrix. These auditing tools can provide you with a loading waterfall chart, which provides data on these key metrics and shows you exactly what happens when a visitor navigates your site and how long it takes your webserver to respond.

Setting and Monitoring Your Performance Budget

The design phase is when your WordPress performance budget can really make a difference. When you have your site speed metrics determined, you can make effective decisions about how to approach page design elements.

For example, you may decide to forgo a heavy carousel on a page if it is going to slow down the load speed too much. Or you may avoid using a third-party font on your pages unless they’re fully optimized to avoid harming your page-load speeds.

Integrating your performance budget into your design phase requires having web vitals monitoring set up on your site’s pages.

Tools for Monitoring

• Google PageSpeed Insights: This tool is helpful for gathering both lab and field data. It provides scores and actionable insights.
• Lighthouse: This open-source, automated tool offers detailed reports on performance, accessibility, SEO, best practices, and progressive web apps (PWAs). You can run audits during development.
• WebPageTest: Mentioned earlier, this tool provides detailed diagnostic information on how your web pages are performing under real-world conditions. It offers deep dives into connection speeds and locations.

Performance budgets lend themselves well to automation. You can use “Budget.json” files or Lighthouse continuous integration (CI) to automatically fail a build or alert a team if a new plugin exceeds the budget already in place on a given page.

Another important consideration with maintaining your WordPress budget performance is your hosting provider. Performance budgets are a lot easier to maintain when the baseline server response time is consistently low. Pressable’s managed WordPress hosting platform is designed for fast page loads and responsive interfaces to best support your high-traffic WordPress site.

Strategies to Stay Under Performance Budget

Once you have your performance budget monitoring tools set up, you can begin to implement some helpful strategies to keep your WordPress pages under budget.

• Image Optimization: Standardize the use of WebP formats for superior compression on your site’s graphics. Also, enable lazy loading so that offscreen images on a requested page are not loaded until the visitor scrolls near them.
• Plugin Auditing: Approach every new plugin as a “tax” on your performance budget. If the plugin adds 50kb or more of Cascading Style Sheets (CSS) or JavaScript (JS) code to the page load but only offers a minor visual change, consider doing without it to avoid this low-value tax.
• Leverage a Content Delivery Network (CDN): Use a global CDN to ensure that the use of a distant server doesn’t break your latency budget. A CDN caches website files on a global network of servers and delivers requested pages from the nearest server for a quicker page load. Pressable’s WordPress CDN helps ensure quick page loads for your visitors.
• Safe Testing Environments: Make use of staging sites to measure the performance impact of a new feature before it hits your production budget. If a new feature negatively impacts your page speeds, you can remove it or make changes so it doesn’t undermine your performance budget. Pressable WordPress staging environments provide one-click access for easy performance benchmarking on your site’s pages.

Designing a Performance-First Site

WordPress performance budgets are not meant to limit creativity with how you design your site’s pages. Rather, they help ensure that creativity doesn’t come at the cost of user experience on the site.

A successful, performance-first site is one that balances the collaborative efforts of developers, designers, and site owners. When all of them are working with the same performance budget in mind, your site gets maximum efficiency and creativity.

Get started today by running a baseline audit of your site’s pages and setting your first time-based and quantity-based metrics on your pages.

Pressable Support for Performance Budgets

Pressable’s managed WordPress hosting platform is optimized to support quick load times on your pages. Our proactive monitoring and alerts, site performance reports, and dynamic resource management all work to help you maintain your site’s performance budgets.

Pressable—part of the Automattic family that also includes WordPress.com, WordPress VIP, and WooCommerce—is staffed by WordPress experts with the skills and knowledge to effectively manage your WordPress site. If maintaining a performance budget across high-traffic WordPress sites is becoming a challenge, schedule a demo to see how Pressable can support your continued optimization and growth.