---
title: "Where do I set the age calculation date?"
categories: [registrations_faq]
updated: 2026-09-23
summary: Set the Age Calculation Date in Settings > Advanced Settings so age-limited options and categories show the right choices.
---
## What the age calculation date does

If your form limits options by age, for example race categories or age-group lessons, Zone4 works out each registrant's age from their birthdate. The **Age Calculation Date** is the day that age is calculated on.

If you don't set one, ages are calculated as of December 31 of the current year. That default moves forward on January 1, so a registration that stays open over New Year can start showing people different categories. If your registration runs across New Year, set the date yourself.

## Set it

1.  Open the registration form and go to the **Settings** tab.
2.  Click **More…**, then **Advanced Settings**.
3.  Enter the **Age Calculation Date** and save.

Use whatever date your sport's age-category rules are based on. Many sports calculate ages as of a fixed December 31 so that athletes stay in the same category all season; others use the race day.

## Age limits need a birthdate and a gender field

Age and gender limits on options only work if your form has **both** the preset **Birthdate** and **Gender** fields. If an age-limited option isn't appearing when it should, check that both are on the form. See [Preset Fields](/kb/preset-fields/).

## The "show all" link

When options are limited by age, registrants see only the options that match their age, plus a link to show all of them. The link lets people register outside their own category, for example an athlete choosing to race up an age group. If someone says they can't see the category they expected, check their birthdate and your Age Calculation Date.

See [Option Fields & Option Fee Fields](/kb/option-fields-option-fee-fields/) for how to set age limits on options.