Add-on plans let you offer additional resources on top of a customer existing hosting plan. For example, you can sell extra disk space or additional domains as add-ons.

### Creating an Add-On Plan

1. Log in to **Plesk**.
2. Go to **Service Plans** → **Add-on Plans**.
3. Click **Create Add-on Plan**.
4. Enter a **plan name** (e.g., "Extra 5GB Storage").
5. Configure the additional resources and permissions.
6. Click **OK**.

### Assigning an Add-On to a Subscription

1. Go to **Subscriptions** → click the subscription.
2. Click **Add Plan** in the right sidebar.
3. Select the add-on plan and click **OK**.

### Important Notes

- Add-on plans are **stackable** — a customer can have multiple add-ons on one subscription.
- Resources from add-ons are added to the base plan.

### Troubleshooting

**"Add-on exceeds reseller limits":**

- Check that assigning the add-on does not exceed your total reseller resource pool.

### Related Guides

- [Base service plans](/hc/help/en/articles/how-to-create-a-service-plan-in-plesk)
- [Modify a plan](/hc/help/en/articles/how-to-modify-an-existing-plesk-service-plan)
- [Change a customer's plan](/hc/help/en/articles/how-to-change-a-customer-service-plan-in-plesk)