If you prefer the new NNM Pace Calculator JS.


With this really easy-to-use tool, especially designed for runners, you can (for example)


The NNM Pace Calculator can be used in many different ways and here I list some of the functionality that I have found useful. You will probably find many other ways to use the calculator. Try it, you'll love it!

Features and functionality

For many more examples of using the calculator, see the examples page, which is an easy way to get started.

User interface

The user interface for the calculator contains three parts that you can fill in: distance, time and pace. There are at most nine input fields that you can fill in (but of course you can't use all fields at the same time).

Valid input values

When you hit the Calculate button, your results will show up. The results are shown in three columns (distance, time and pace), and depending on what input values you have defined either one or all of these columns are shown. The distance and pace columns contain several rows showing you the results in several units. You can configure the units you want to use.

Target split times

If you have defined a value for Split distance in you will also see a table for the target split times.

An example is the best way to describe the target split times table. Suppose you want to run a marathon in 4 hours and you want to know your goal times for certain split distances. It is easy! Just define the distance as 42195 meters, the time as 4 hours and the split distance in as kilometers. Hit the Calculate button and you will get these target split times for each kilometer. If you prefer to see the target split times in miles (instead of kilometers), just change the split distance in to miles. Then you see the target split times for each mile instead.


On the configuration page you can define your personal settings for the calculator. If you haven't defined any personal settings the default will be used.

Distance configuration

For each unit of distance, you have two checkboxes. With the first checkbox you define if you want the unit to be shown in the distance dropdown list. With the second checkbox you define if you want the unit to be shown in the split distance in dropdown list.

To be able to use the calculator you need to have at least one distance unit selected. You don't need any split unit.

Time configuration

Since there (at the moment) is just one way of defining the time, you have no choices here. The only choice available for time is therefore always selected, since you need at least one time unit selected to be able to use the calculator.

Pace configuration

Here you define the different units of pace that you want to use.

To be able to use the calculator you need to have at least one pace unit selected.

How your settings are stored

Your personal settings are stored as a cookie in your browser, so your settings can be remembered between your requests.

If you push the Save configuration values button your choices will be stored in a cookie with the name NNMPaceCalculator. The cookie will contain your defined distances, split distances and paces.

If you instead push the Reset to defaults button your choices will be removed and you will get the default choices. The reset is accomplished by removing the NNMPaceCalculator cookie from your browser.

The Set all and Clear all buttons are convenient ways for marking/unmarking all checkboxes. No new configuration values are stored just by using these two buttons, so to make your settings persistent you have to push Save configuration values (and allow cookies).

Default values

The default values may change from time to time. The easiest way to see what they currently are is to click the Reset to defaults button.


If the calculator is not working correctly or as you expect, you may find the reasons in the following remarks:



The relationship between the distances compared to SI-unit 1 m.

The relationship between the paces and speeds compared to SI-unit 1 m/s.

Note: The metric length system that is used nowadays is built around the number 10. For those using inches, feet, yards and so on, it is not that "easy", so here is a reminder:


The really simple mathematical formula that lies behind most of the calculations is of course

    d = v * t

where d (unit m) is the distance, v (unit m/s) is the speed/pace and t (unit s) is the time.

How to calculate the number of rows in the TargetSplitTimes table

Assume that you have the following definitions

    x = total number of elements   (known variable)
    y = rows per column            (unknown variable)

The equation will then be

    y = ( floor( ( x - 1 ) / ( MAX_SPLIT_ROWS * SPLIT_INTERVAL ) ) + 1 ) * SPLIT_INTERVAL

With the example values from above

    y = ( floor( ( x - 1 ) / 50 ) + 1 ) * 10

or as a table

    ______x_____    _y_
      1 ...   50 =>  10
     51 ...  100 =>  20
    101 ...  150 =>  30
    151 ...  200 =>  40
    201 ...  250 =>  50
         :       :
    901 ...  950 => 190
    951 ... 1000 => 200

So if you have 43 splits (for example a marathon splitted in kilometers) the resulting target split times table will contain 10 rows (and 5 columns), which you can see here for Dennis Kimetto's world record in marathon.

References at Wikipedia


If you have any questions, don't hesitate to contact me.