Privacy
You can use the ruler without creating an account. Some optional features contact external services.
Last updated: 21 September 2026.
Settings in your browser
The app stores calibration and display preferences in browser storage. It also uses a session preference when you hide the ad banner. Clearing this site's storage removes saved settings. If storage is blocked, the ruler uses temporary in-memory preferences for that page visit.
Device matching and community calibration
The app can read the model hint supplied by your browser, screen dimensions and pixel ratio to look for a local device preset. If no local match is available and a useful model hint exists, it can send the model hint and screen dimensions to the calibration service hosted on Supabase to look for a compatible shared template. Device searches can also query that service.
If you choose Online Device Match, the matching service receives device information to find display specifications, and may query MobileAPI. This feature is optional. If you choose Share calibration, the displayed device model or model aliases, dimensions, diagonal and adjusted scale are submitted to the shared calibration database so other visitors can use them.
Do not enter your name, email address or other private information as a device name: shared model labels are intended to describe devices. The calibration service uses a short-lived rate-limit token derived from connection information to reduce abuse. Requests also expose network information, such as an IP address, to the service handling them.
Motion sensors and camera
The bubble level uses device orientation readings when supported and permitted by your browser. Camera-based Big Ruler requests a WebXR session on compatible devices. The app uses these readings in the browser to display measurements; its application code does not upload camera images or motion readings to the calibration service. You can deny or revoke the browser permission and still use the ordinary ruler.
Advertising
Screen Ruler uses Google AdSense. Google and its advertising partners may use cookies, IP addresses and other identifiers to serve and measure ads, including personalising ads where permitted. Read how Google uses information from sites that use its services and manage your preferences through Google My Ad Center.
Holding the settings button for five seconds hides the banner for the session; holding it for ten seconds reveals the persistent Disable Ads toggle in Tools. Hiding a banner does not undo requests already made or remove cookies that a provider has set. Browser privacy controls can restrict cookies and site storage.
Hosting and external links
Loading the site involves requests to its hosting provider, which receives connection details needed to deliver files and may keep operational logs. Following a link to GitHub, LinkedIn or Google brings you to that provider's site and privacy practices.
Questions
Use the public profiles on the Contact page to reach the developer. Do not post passwords, account tokens or other sensitive details in a public report.