About

About pacvivo

pacvivo is a free, no-signup running pace calculator. It converts between pace, distance and finish time in an instant, and uses the Riegel formula to project marathon, half-marathon, 10K and 5K times from any recent race result.

The tool runs entirely in your browser. Your numbers never leave your device — no account, no tracking of your runs, no server-side storage of calculations.

We built it for runners who want a target split they can trust before race day, and a prediction they can take to training. Pick the mode that matches what you know, enter your time or pace, and get an answer you can act on.

Made by runners, for runners.