diff --git a/docs/lovelace_custom_card.md b/docs/lovelace_custom_card.md
index d8c92f25..727ce471 100644
--- a/docs/lovelace_custom_card.md
+++ b/docs/lovelace_custom_card.md
@@ -9,6 +9,7 @@ You're not just limited to the cards that we decided to include in the Lovelace
 - You define your custom card as a [custom element](https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_custom_elements). It's up to you to decide how to render your DOM inside your element. You can use Polymer, Angular, Preact or any other popular framework (except for React – more info [here](https://custom-elements-everywhere.com/)).
 - Home Assistant will set the `config` property when the configuration changes (rare).
 - Home Assistant will set the `hass` property when the state of Home Assistant changes (frequent). Whenever the state changes, the component will have to update itself to represent the latest state.
+- Home Assistant will call `getCardSize()` to request the size of the card. Size of the card is used for the automatic distribution of cards across columns. Both `config` and `hass` properties will be available. Defaults to `1` if function is not defined.
 
 ## Defining your card
 
@@ -162,4 +163,4 @@ views:
       - input_boolean.switch_ac_kitchen
       - input_boolean.switch_ac_livingroom
       - input_boolean.switch_tv
-```
\ No newline at end of file
+```