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Free tools

Small interactive tools that answer one question properly. No signup, no email, no paywall, nothing hidden behind a form. Each one shows its formula and links the primary source behind every coefficient — if we cannot cite a number, it does not ship.

Available now

In the works

Listed so you know what is coming, not to pad the site. There are no empty pages behind these — they appear above once they actually work.

  • Sweat Rate Calculator Measure how much fluid you actually lose per hour
    Planned

    Weigh in before and after a session and get your personal sweat rate, using the formula from the NATA fluid-replacement position statement. Feeds a far more accurate number into the water calculator than any intensity band can.

How these are built

  • Sourced coefficients. Every constant traces to a named document — a reference body, a position statement, a peer-reviewed trial. Anything we estimate ourselves is labelled as an estimate in the interface.
  • The math is visible. You get the breakdown, not just the answer, so you can check whether the assumptions fit you.
  • Ranges over false precision. Where the underlying science gives a range, the tool gives a range.
  • Nothing gated. No account, no email capture, no export paywall. Results share as a link or an image because that is useful, not because it farms contacts.

Built by Alec Zakhary — a product manager, not a dietitian. These are estimation tools for healthy adults, not medical advice. See the editorial policy and source citation policy.