About Marathonic

Marathonic.run is a free collection of running calculators and training plans built for one thing: helping you run smarter. Whether you're nervously eyeing your first 5K or chasing a sub-4 marathon, the right numbers make the difference between a good day and a hard lesson.

Every tool here is designed to be fast on your phone — because that's where you actually use them: at the track, on the start line, in the gym. They work in both kilometres and miles, need no account, and load in a blink.

The science we use

• Race prediction — the Peter Riegel formula (1981), the endurance world's standard model.
• Age grading — World Masters Athletics (WMA) road standards and age factors.
• Heart rate — the Tanaka max-HR estimate, the Karvonen heart-rate-reserve method, and Maffetone's MAF 180.

Our calculators are educational tools, not medical or coaching advice. Check with a doctor before starting a new training programme, especially if you have any health concerns.

Questions or spotted a bug? Email support@willgo.tech.