Browser RAM Checker

Inspect browser heap values, a privacy-limited device-memory estimate, and a small allocation test. This does not diagnose physical RAM health or measure hardware memory bandwidth.

RAM Checker

Displays browser memory usage and approximate device memory when APIs are available. Run the allocation test to compare browser memory write behavior.

performance.memory not available

The performance.memory API is only available in Chromium-based browsers (Chrome, Edge, Brave). Firefox and Safari do not expose heap memory information. You can still run the allocation speed test below.

Note: JS heap size reflects memory used by the JavaScript engine, not total system RAM. The allocation test fills a 50MB Float32Array to compare browser memory behavior. Device memory is an approximation rounded and capped for privacy.

Browser Memory APIs

Modern browsers expose limited memory information through the Performance API. The performance.memory API in Chrome provides insight into JavaScript heap usage, while the Device Memory API allows websites to adapt to different RAM configurations. These APIs help developers optimize web applications for a range of device capabilities.

The allocation test measures how long this browser takes to allocate and write to a 50MB block of memory. JavaScript engine behavior, garbage collection, and system load all affect the result, so it is useful for rough comparisons between runs rather than as a hardware memory-bandwidth benchmark.

What Browser Memory APIs Can Show

JavaScript heap usage

Chromium browsers can expose memory used by JavaScript objects in the current browser process.

Approximate device memory

The Device Memory API rounds physical RAM into broad buckets and caps values for privacy protection.

Not installed RAM exactly

A browser page cannot read exact RAM modules, memory channel configuration, swap usage, or system-wide process memory.

Useful for web app diagnostics

Use this page to compare browser memory behavior before and after opening heavy web apps, extensions, or dashboards.

RAM Checker FAQ

Common questions about browser memory APIs, JS heap size, deviceMemory, and allocation speed testing.

The RAM Checker displays three values from the performance.memory API (Chrome/Chromium only): JS Heap Used (memory currently in use by JavaScript objects), JS Heap Total (total allocated heap space), and Heap Limit (maximum allowed heap size). It also shows navigator.deviceMemory if available, which reports a privacy-limited approximation of device RAM. The allocation test times how long this browser takes to allocate and fill a 50MB Float32Array. It is not a hardware memory-bandwidth benchmark.

The performance.memory API is a non-standard Chrome extension to the Performance interface and is intentionally not available in Firefox or Safari. Mozilla and Apple have declined to implement it citing privacy concerns — memory usage patterns could potentially be used for fingerprinting. Chrome exposes it only in non-cross-origin contexts. The allocation speed test and navigator.deviceMemory still work in most modern browsers.

The Device Memory API (navigator.deviceMemory) returns the approximate amount of device RAM in gigabytes, rounded to the nearest power of 2 (e.g., 0.25, 0.5, 1, 2, 4, 8). The maximum value reported is 8 GB regardless of actual RAM to prevent fingerprinting. It is supported in Chrome, Edge, and Samsung Internet but not in Firefox or Safari. It allows websites to serve lighter resources to low-memory devices.

JS Heap Used represents the amount of memory currently occupied by live JavaScript objects including strings, arrays, objects, closures, and compiled code. This value changes continuously as objects are created and garbage-collected. High heap usage relative to the heap limit may cause performance issues or tab crashes. Running this test alongside heavy web apps can reveal memory leaks where heap usage grows continuously without returning to baseline.

Browser memory usage is affected by the number of open tabs, installed extensions, size of loaded images and media, JavaScript application complexity, and memory leaks in web applications. To reduce usage: close unused tabs, disable or remove extensions, avoid keeping large media-heavy pages open indefinitely, and use the browser's task manager (Shift+Esc in Chrome) to identify which tabs are consuming the most memory. Some browser flags can also adjust memory limits.

Related Hardware Tests

Continue with another check for the same device or signal.

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