Fitness

The most widely used method is the Karvonen formula, which factors in both maximum heart rate and resting heart rate to produce a heart rate reserve (HRR). Training zones are then set as percentages of that reserve, added back to resting heart rate. A simpler method uses only maximum heart rate (estimated as 220 minus age) without accounting for fitness level. The target heart rate calculator shows the Karvonen result but notes where the simpler formula gives a different answer.

VO2 max is the maximum rate at which your body can use oxygen during intense exercise — a standard measure of aerobic fitness. Laboratory testing requires a controlled exercise test with respiratory gas analysis. Field estimates use proxy measures such as running time over a fixed distance, a step-test recovery heart rate, or submaximal cycle ergometer protocols. These estimates carry wider uncertainty than lab tests but are useful for tracking relative fitness changes over time.

Enter your target finish time and race distance to see the required pace per kilometre or mile. Alternatively, enter your current training pace to project a finish time. The pace calculator also breaks your race into splits so you can plan even-effort or negative-split pacing strategies. For longer races such as half marathons and marathons, a conservative early pace that you can sustain is usually more effective than going out at your target average.