# Run Time Calculator

Our run time calculator enables you to predict how long it will take you to run a certain distance using your past run times and the run time prediction formula of your choice.

How to use the calculator:

1. Choose the run time prediction equation you wish to apply
2. Enter your previous run time and distance
3. Enter the distance for which you wish to calculate your run time using the drop-down menu or custom option
4. Click on the "Calculate" button to generate the results.
Run Time Prediction Calculator

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Results
Estimated Time:

## Run Time Prediction Equation 1: Riegel's Equation

Riegel's equation is among the simplest formulas for calculating run times. It does not rely on units of measurement, meaning that it is not necessary to convert distances and times.

T2 = T1 * (D2 / D1)1.06

In this equation, T1 represents your previous run time, D1 your previous run distance, D2 the distance you wish to calculate a new run time for, and T2 is your estimated new run time. Provided that all distances are of the same unit of measurement (e.g. all in miles, all in kilometers), you can use any unit of distance you wish.

This equation applies an exponent that is greater than 1 (1.06), indicating that your velocity when you run is considered to decrease over longer distances, resulting in a significantly increased run time. That is, when, for example, you run double the distance of a previous run, the time it is anticipated it will take you to cover this distance will rise by 21.06, a factor of approximately 2.084932. In contrast, if you were to run half a previous distance, your run time would decrease by 0.51.06 or a factor of 0.479632.

## Run Time Prediction Equation 2: Cameron's Equation

Another popular run time prediction formula is Cameron's equation, which uses data from previous runs to predict future performance.

T2 = T1 * [D2 / D1] * [f(D1) / f(D2)]

In this equation, T1 represents your previous run time, D1 your previous run distance in meters, D2 the distance you wish to calculate a new run time for, and T2 is your estimated new run time. The f(x) function is described as:

f(x) = 13.49681 − 0.000030363 * x + 835.7114 / x0.7905

The action of factor f(D1) / f(D2) is to increase your time by a marginally larger factor than any distance increase. Conversely, it also decreases your time by a marginally smaller factor than any distance decrease.

## Run Time Prediction Equation 3: Daniels & Gilbert VO2 Max Equation

This run time formula uses the maximum level of oxygen you consume when engaging in incremental exercise to calculate run times, with VO2 max referring to maximum aerobic capacity or maximum oxygen consumption.

Over shorter timespans, the VO2 max rate of a runner will remain generally the same. The Daniels and Gilbert VO2 max equation can be used to predict future run times based on previous performance. Specifically, the VO2 max rates and new distance of a run can be used to predict how long it will take a runner to cover this new distance.

The equation is as follows:

VO2 max = (−4.60 + 0.182258 * v + 0.000104 * v2) / (0.8 + 0.1894393 * e−0.012778*t + 0.2989558 * e−0.1932605*t )

As it is not possible to rearrange the equation algebraically to isolate the time element, numerical algorithms are needed to deal with time. In this equation, v represents velocity (in meters/min) and t represents the time in minutes. The VO2 max rate is described as ml/(kg•min).

You may also be interested in our free Pace Calculator