Security

Privacy by design, built into how every calculator works.

How processing works

Each calculator is a program that loads into your browser and runs on your device. Lengths, bag counts, and prices stay in the tab. The shopping list, if you use it, is saved in localStorage on this device only.

Check it yourself

Open your browser’s developer tools, choose the Network tab, and run any calculator. You will see no request carrying your project sizes.

Responsible disclosure

Found a vulnerability? Email hello@buildmathhq.com with “Security” in the subject line. We aim to acknowledge reports within 5 working days. Do not open a public issue until we have released a fix. The same contact is listed in /.well-known/security.txt.