Running calculators & training plans
that actually make you faster
Dial in your pace, predict your finish time, find your heart-rate zones and follow a plan built to get you to the line. Free, instant, and works in km or miles.
The calculators
Everything updates instantly as you type. No account, no fluff.
Marathon Pace Calculator
Enter a target time and distance — get your exact pace plus a printable split-time band for race day.
Open tool → 🔮Race Time Predictor
Turn a recent 5K or 10K into a realistic half or full marathon finish-time prediction (Riegel formula).
Open tool → 🏅Age Grade Calculator
Score any result against the WMA world standards for your age and sex. See how you really stack up.
Open tool → ❤️Heart Rate Zones
Five training zones from Max HR, Karvonen reserve, or MAF 180. Re-check it every time your fitness shifts.
Open tool →Training plans
Free, structured and printable — with the right calculator built into every plan.
Why runners use Marathonic
Whether you're lacing up for the first time or chasing a personal best, the numbers matter. The right pace keeps you from blowing up at halfway. The right heart-rate zones keep your easy days truly easy so your hard days count. And an honest finish-time prediction tells you what's realistic before you toe the start line.
Marathonic puts the calculations the sports-science world relies on — the Peter Riegel prediction model, WMA age-grading standards and the Karvonen and MAF heart-rate methods — into tools that load in a blink on your phone, right there at the track or on the start line.