Two years ago, Slate ran a marathon prediction calculator ... Their new formula uses these two inputs to calculate a predicted time.

For comparison's sake, we'll provide you Slate's prediction and one using Runner's World's formula ... slower than the actual time. But if you’re using a calculator to pace yourself, Vickers ...

The formula for ... for distance and time. In this example, distance is in metres (m) and time is in seconds (s), so the units will be in metres per second (m/s). To calculate one of the variables ...