Contact Us

Found a mistake, have a question, or want to suggest a new calculator? We read everything.

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What to include

• Bug reports: the tool name, your device/browser, and the values you entered — we can usually fix same-week.
• Formula questions: every tool lists its sources at the bottom of the page; cite the section and we'll gladly go deeper.
• Privacy questions: mention "Privacy" in the subject — see also our Privacy Policy.
• Tool suggestions: we build tools only where an evidence-based, honest version is possible.

We usually reply within a few days.

Meanwhile, explore the tools