About Ryutility

Ryutility is a small, independent collection of free web tools. The goal is simple: solve one specific, everyday problem per tool, load fast, work on any device, and get out of your way — no account required, no unnecessary clutter.

The first tool, the Training Zone Calculator, turns a recent race time into personalized running training paces using Jack Daniels' VDOT method. More tools are added over time, always with the same philosophy: useful first, simple always.

Ryutility is built and maintained independently. If something is broken or you have a suggestion, see the Contact page.