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How to Calculate Age from Date of Birth in a Race

Here you will learn how to calculate racer ages based off of their Date of Birth (DOB).

This can be useful if you want to use age ranges to group your racers in your start list or results, but only collected Date of Birth on your registration.

First go into your race file and navigate to the Racers page by clicking the Racers button at the top of the page.

In the Racers page scroll down to Race Tools and click on the Calculate Ages option.

This will open the Calculate Racer Ages window.

Here you will need to enter 3 things:

  1. Age Calculation Date
  2. Birthdate Field
  3. Age Field

Age Calculation Date

In order to calculate someone’s age you need two dates: their birth date and another day somewhere in the future — ie. the Age Calculation Date. You can then calculate the number of years between the two dates to determine the racer’s age.

The age calculation date is important for finding a racer’s age on a given day. For example, if your Age Calculation Date is May 4th 2018 and someone is born May 7th 2000, your racer’s calculated age will be 17 and not 18. However, if your racer’s birth date is May 2nd 2000 and the same Age Calculation Date is used then that racer’s calculated age will be 18.

For most races, the Age Calculation Date will be the day of the race.

However, some race formats might require using a different date. For example, in cross country skiing ages should be calculated on Dec 31 of the year the current season ends, so a race in November will use Dec 31 next year and a race in February will use Dec 31 in the current year, so that racers stay in the same category all winter.

You can set the Age Calculation Date by either typing it directly into the text box or using the calendar to the right and selecting a date.

Birthdate Field

Next you need to select the racer data field where you stored the racer’s date of birth.

If you imported your racers from a registration with a birth date field or from a CSV file with a “DOB” column, that field will automatically be used as your Birthdate Field. Otherwise, you will need to select which field the date of birth is stored in.

To select your Birthdate Field click the arrow on the right and select the correct data field from the list, as shown below.

Age Field

Next you need to select which racer data field the calculated age will be stored in.

If you have a field in your race called “age”, that field will automatically be selected.

If you don’t have an age field on your registration, you can leave the Store in new field option selected and an Age field will automatically be added to all your racers.

You can also select an Age Field by clicking the arrow on the right and selecting the desired data field from the list, as shown below.


After you’ve selected an Age Calculation Date, a Birthdate Field and an Age Field click the Calculate Ages button in the bottom right corner.

Each racer will now have an Age field with their calculated age.

If you update the racer’s date of birth or import new racers, their ages will be calculated automatically, so you only have to go through this process once per race.

These ages can now be shown on start lists and results, and you can use them to create age groups for results and start lists. 

Updated on 2019-06-27

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