About Zone2Cal
A small tool built for runners
Hello! I'm the developer behind Zone2Cal, a fellow runner obsessed with Zone 2 training, tempo sessions, and sustainable mileage. The goal was simple: gather marathon pace prediction, treadmill pace conversion, MAF heart-rate planning, and fueling math on a single responsive page.
🤔 Why Did I Build This?
During training blocks I kept juggling multiple tabs to answer questions like “What marathon time does my 10K translate to?”, “How fast should 400m reps be for VO₂max intervals?”, or “Where does my Maffetone cap fall today?”. Scattered data and clunky mobile UI/UX slowed everything down, so I built a unified tool.
"One intuitive dashboard for race prediction, treadmill pace conversion, Zone 2 / MAF guidance, and fueling estimates—no spreadsheets required."
🧰 What's Inside?
- Race Predictor & Split Planner — Riegel-based goal times, weather offsets, CSV pace plans, and 1 km/5 km split tables.
- Zone 2 · MAF · LT Tools — % Max HR vs. Karvonen, Maffetone 180, plus an LT calculator that suggests tempo and cruise-interval intensities automatically.
- Treadmill & Track utilities — Instant km/h ↔ min/km and mph ↔ min/mile conversion, with 400 m lap splits for track sessions.
- Marathon Schedule Page — Automatically updated major race dates and registration links for Korea and global events.
🎯 What We Value
Every feature is grounded in evidence—Riegel, Karvonen, Maffetone, 80/20 endurance theory, and current LT research—so you can train longer without injury. All calculations run locally in the browser, meaning no personal data ever leaves your device and Garmin/Strava exports pair seamlessly with the results.
📚 Keep Up With Updates
The latest race timeline lives on the Marathon Schedule page, and broader product updates will be reflected here as the site evolves. The Korean edition stays in step.