Legal

Terms of Service

Last updated: October 2026

The following terms apply to pacvivo.com (the "Site"). Acceptance is implied by use, so if they are not acceptable to you, please stop using the Site.

The tool this page covers is PacVivo, a running pace and race-time calculator. Put simply, it converts between pace, distance and finish time and predicts marathon, half-marathon, 10K and 5K times from a recent race, and the way it does so is this: it predicts using the Riegel formula, where the predicted time scales as the ratio of the distances raised to the power 1.06, which is why an equivalent performance at twice the distance is a little slower than twice the time. Everything stated here applies to that tool and the values it handles, and to nothing else.

In day-to-day use the tool works only from your recent race time and distance, and it is usually opened for things like setting a target pace for a marathon. None of that reaches us, so none of it can be stored.

The service we provide

The Site provides a running pace and race-time calculator and explanatory material, free of charge, for general information and education. Results are estimates derived from the inputs you supply using the method described on the page. Results are provided for general information and convenience, and should be verified where a decision matters.

No duty of care created

Nothing here forms a client, advisory or fiduciary relationship. The Site is a tool, and how you act on its output is a matter for you.

Acceptable use

Use the Site freely for yourself or your work. What is not allowed: disrupting the service, scraping it hard enough to hurt performance for others, claiming it as your own, or any unlawful purpose.

Intellectual property

The design, text and code of the Site belong to us or are licensed to us, except where credited otherwise. You may link to any page. Reproducing substantial parts of the content requires written permission.

Third-party content and advertising

Advertising, served by outside networks, funds the Site, and some pages reference external resources. We do not control that material and are not answerable for it, and no advert influences a result.

Changes and downtime

The Site is provided "as is". We may change, suspend or remove any tool or page at any time and do not guarantee uninterrupted availability.

Limits on our liability

To the fullest extent permitted by law we are not liable for indirect or consequential loss, or for any decision taken in reliance on a result from the Site.

Which law applies

The terms are governed by the law of the jurisdiction in which the Site operator is established, conflict-of-law rules aside.

When accuracy matters

These tools give a quick general answer. For anything with consequences, verify the result independently before you rely on it.

Errors and completeness

We aim for correctness and document the method behind the tool. We do not warrant that every result is free of error, or that the content is complete or current. Where a method carries a recognized margin of error, the result should be read as an estimate.

Asking about these terms

Anything unclear in these terms can be raised through the contact page.