Privacy Policy
Last updated: January 2026
This Privacy Policy explains how the Online Ruler website ("we", "us", "the tool") collects, uses, and protects information. We built this tool to run entirely in your browser, so the short version is simple: your measurements never leave your device.
Information We Collect
We do not require an account, and we do not collect personal information to use the ruler. The only data stored is kept locally on your own device:
- Calibration settings — your screen's pixels-per-inch (PPI) value, saved in your browser's local storage so the ruler stays accurate on return visits.
- Theme preference — whether you chose light or dark mode.
- Tool settings — which units and tools you last used.
What We Do NOT Collect
- We do not upload, transmit, or store any measurements, screenshots, or drawings you make.
- We do not use cookies for advertising or cross-site tracking.
- We do not sell or share personal data with third parties.
Analytics
We may use privacy-friendly, aggregated analytics (such as page-view counts) that do not identify you individually. This helps us understand which features are useful so we can improve the tool. No measurement data is ever included in analytics.
Local Storage
Data such as calibration and theme is stored using your browser's localStorage API.
You can clear it at any time by clearing your browser data for this site. Doing so simply resets
the ruler to its defaults — no information about you is lost elsewhere, because none was sent.
Camera Permission
If you use the optional camera-based measuring mode, video from your camera is processed on-device only. We do not record, upload, or retain any camera images or video. You can revoke camera access at any time from your browser's site settings.
Children's Privacy
This tool is safe for general use and does not knowingly collect information from children under 13. Because no personal data is collected, there is nothing to disclose to third parties.
Changes to This Policy
We may update this Privacy Policy occasionally. Material changes will be reflected by the "last updated" date above. Continued use of the tool after changes means you accept the updated policy.
Contact
Questions about this policy? Reach us through the contact page.