Answers to common questions about using Trendy String's calculators and tools.
No. Every calculator on Trendy String works instantly in your browser — no sign-up, no account, no email required.
The numbers you enter (height, weight, blood pressure readings, etc.) are processed in your browser and are not sent to or stored on our servers tied to your identity. The Health Tracker tool stores your entries locally so you can see trends over time — see our Privacy Policy for details.
Yes, completely. Every tool on this site is free to use, with no limits and no premium tier.
Each calculator uses an established, publicly documented formula (see our Methodology page). Results are educational estimates based on population-level data — not a diagnosis. See each calculator's own page for notes on its specific accuracy and limitations.
Try refreshing the page first. If the issue continues, let us know via our Contact page with the calculator name and a description of what you're seeing.
Absolutely — we're always expanding our tool library. Send your idea through the Contact page.
Not currently — all calculators work directly in your mobile or desktop browser, so there's nothing to download.
Visit our Journal for in-depth explainers on many of our most-used tools, or check the Formula Sources page for a quick reference table.