Update Device Memory API limits

at a glance

syntax

The two surfaces whose reported values change — the JavaScript getter and the client-hint header — keep their existing syntax from the Device Memory specification:

// JavaScript (Window and Worker contexts, secure contexts only)
partial interface mixin NavigatorDeviceMemory {
  readonly attribute double deviceMemory;
};

// HTTP client hint (ABNF, quoted from the spec)
Sec-CH-Device-Memory = sf-decimal

A reported value is the device’s RAM rounded to the nearest power of two (in MiB, then divided by 1024 to yield GiB), clamped to an upper and a lower bound. Per PR #53 those bounds are implementation-defined, “may differ on different device types”, and exist so the range “exclude[s] rare device memory values to mitigate” fingerprinting (spec wording). Chrome 147’s new bounds are the table below; the legacy Device-Memory header (see MDN) reports the same bucketed value where still enabled.

what changed

The Device Memory API reports RAM in privacy-preserving buckets rather than the exact amount. Chrome 147 updates these buckets to reflect current hardware in 2026:

The low-end buckets (0.25 GB and 0.5 GB) are removed on Android — virtually no current Android device ships with less than 1 GB RAM. The upper range on desktop expands to 16 GB and 32 GB to accommodate high-end workstations.

reading device memory

// navigator.deviceMemory returns one of the new bucket values
console.log(navigator.deviceMemory);
// Android: 1, 2, 4, or 8
// Desktop: 2, 4, 8, 16, or 32

// Code that relied on values below 1 will never match on Android in Chrome 147+
if (navigator.deviceMemory < 1) {
  // This branch is now unreachable on Android
  showLowMemoryMode();
}

Client Hint HTTP exchange (a specification example, not a captured Chrome request): the server opts in on a response, and a compatible browser can send a bucket on a subsequent request.

# Server response
Accept-CH: Sec-CH-Device-Memory

# Subsequent browser request, as illustrated by the Device Memory specification
GET /example HTTP/1.1
Sec-CH-Device-Memory: 8

browser compatibility

Per-version data for navigator.deviceMemory from BCD api/Navigator.json (verified 2026-09-20), which records this bucket change directly in its version notes:

Baseline: limited availability per the device-memory web-feature on webstatus.dev (queried 2026-09-20). Treat the API as a Chromium-only progressive enhancement.

security and privacy

Bucketing exists precisely for privacy: the Device Memory specification requires the reported value to be rounded and bounded so the range “exclude[s] rare device memory values”, mitigating fingerprinting; the API and the Sec-CH-Device-Memory hint are limited to secure contexts, and the hint is opt-in via Accept-CH, with cross-origin delivery controlled by the ch-device-memory Permissions Policy feature (default allowlist self) in Client Hints Infrastructure. Chrome 147’s change reduces entropy on Android (four buckets instead of six) and adds two high-end desktop buckets (16, 32); the bounds remain implementation-defined per PR #53 so they can track the device landscape without spec churn.

see also

• MDN: Navigator.deviceMemory
• MDN: Device-Memory header (URL updated to MDN’s new layout, 2026-09-20)
• Device Memory specification (W3C) · PR #53 — implementation-defined bounds (merged 2026-01-19)
• chrome-platform-showcase: Device Memory demos (five concepts, route 200)
• ChromeStatus — Update Device Memory API limits (6330376953921536)
• blink-dev Intent to Ship — Update Device Memory API limits