# Proration

When an existing subscription is updated or a new subscription is added to an account that already has a subscription, proration typically comes into play as that those changes rarely fall exactly at the end of a billing period, which means that the change will be for a partial period.

For example, if an account has a subscription that runs from January 1 to December 31 and that subscription is changed April 1, the annual charges must be prorated remaining 9 months of the year.

<figure><img src="/files/cmkmdsr9qnyduIKKlrmg" alt=""><figcaption><p>Proration</p></figcaption></figure>

Bunny will automatically suggest subscription end dates that are aligned with existing subscriptions, but you also have the option to choose a custom date.


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