Browser Performance Timing

Inspect your browser's real navigation timing, resource waterfall, and Core Web Vitals - all read live from the Performance API.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

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Resource Type Size Duration (ms) Waterfall
Loading performance data-

How to Use the Browser Performance Timing Tool

To use the Browser Performance Timing Tool, simply load the page. The tool will automatically capture timing data when the page loads. You can switch between the three tabs to explore different views: Navigation, Resources, and Core Web Vitals.

  • Load the page to capture timing data automatically.
  • Switch between Navigation, Resources, and Core Web Vitals tabs to explore different views.

When to Use the Tool in Real Workflows

Use the Browser Performance Timing Tool to analyze the performance of your web pages. Identify bottlenecks, understand resource loading times, and optimize your site for better user experience.

How It Works

The Browser Performance Timing Tool uses the Performance API to capture detailed timing data for your browser's navigation and resource loading. The data is displayed in a visual waterfall chart and can be filtered by resource type. Key metrics include DNS lookup, TCP connect, TTFB, DOM processing, and more.

Tips, Edge Cases, or Limitations

Ensure your browser's JavaScript is enabled for accurate timing data. The tool captures data client-side, so no data is sent to a server. Be aware that the tool may not capture data for cross-origin requests due to browser security restrictions.

  • JavaScript must be enabled for accurate timing data.
  • Data is captured client-side, no data sent to a server.
  • Cross-origin requests may not be captured due to browser security restrictions.

Frequently Asked Questions

TTFB (Time to First Byte) measures the time from the end of the request until the first byte of the response arrives. This includes your server's processing time and is one of the most important metrics for perceived load speed.
Core Web Vitals are a set of key metrics that help you understand the user experience of your web pages. They include Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS).
LCP (Largest Contentful Paint) measures the time it takes for the largest above-the-fold content to be painted to the screen. It is one of the Core Web Vitals and is an important metric for perceived load speed.
DNS lookup can be slow due to various factors such as the speed of your DNS resolver, the geographic distance between your location and the resolver, and the number of DNS queries made. Using a fast DNS resolver can help improve DNS lookup times.
No, the Browser Performance Timing Tool captures data client-side and does not send any data to a server. All data is stored locally in your browser.