# Adjust an estimated authorization

If you've [performed an estimated authorization](https://www.checkout.com/docs/payments/manage-payments/authorize-a-payment.md#Request_an_estimated_authorization), you can request an incremental authorization to increase one of the following:
- The original authorization amount for Visa and Mastercard globally, and American Express in the United States.
- The authorization's validity period for Mastercard and Mada.

For example, a car rental agency may need to increase the authorization amount when a vehicle is returned due to additional fees.

> **Information**
>
> Mastercard and Mada refer to estimated authorizations as 'preauthorizations'.

> **Information**
>
> Incremental authorization and [overcapture](https://www.checkout.com/docs/payments/manage-payments/capture-a-payment/overcapture-a-payment.md) are separate features. Although they can achieve similar outcomes, they work differently and are not interoperable. See [What is the difference between incremental authorizations and overcaptures?](https://support.checkout.com/hc/en-us/articles/39052317690514)

---

## Increase an authorization's amount

An incremental authorization increases the original authorization amount by the amount you specify in the request. The final authorization amount will be the sum of the estimated authorization and all subsequent incremental authorizations.

> **Note**
>
> You cannot increase the original authorization amount for Mada cards.

You can perform any number of incremental authorizations within the [estimated authorization's validity period](https://www.checkout.com/docs/payments/manage-payments/authorize-a-payment.md#Estimated_authorization_validity_period). However, you cannot perform any further incremental authorizations once you have fully or partially [captured the payment](https://www.checkout.com/docs/payments/manage-payments/capture-a-payment.md).

Call the [Increment authorization](https://api-reference.checkout.com/tag/Payments/#operation/incrementPaymentAuthorization) endpoint, setting the payment ID returned in the original authorization's response, as the `{id}` path parameter.

> **Information**
>
> Your base URL's `{prefix}` value is unique to your account and environment. To learn how to retrieve your base URLs for the sandbox and production environments, see [API endpoints](https://www.checkout.com/docs/developer-resources/api/api-endpoints.md).

**Production**

`POST` `https://{prefix}.api.checkout.com/payments/{id}/authorizations`

**Sandbox**

`POST` `https://{prefix}.api.sandbox.checkout.com/payments/{id}/authorizations`

### Request example

```json
{
    "amount": 100,
    "reference": "ORD-5023-4E89",
    "metadata": {
      "partner_id": 123989
    }
}
```

### Response example

```json
{
  "action_id": "act_oqpt7d4wacaexa7aoupddxlvtm",
  "amount": 100,
  "currency": "USD",
  "approved": true,
  "auth_code": "410961",
  "scheme_id": "168679383391401",
  "response_code": "10000",
  "response_summary": "Approved",
  "risk": {
    "flagged": false
  },
  "reference": "ORD-5023-4E89",
  "processed_on": "2023-06-21T17:17:25.4737666Z",
  "processing": {
    "acquirer_transaction_id": "900604935930035384724",
    "retrieval_reference_number": "444143809558"
  },
  "balances": {
    "total_authorized": 200,
    "total_voided": 0,
    "available_to_void": 200,
    "total_captured": 0,
    "available_to_capture": 200,
    "total_refunded": 0,
    "available_to_refund": 0
  },
  "expires_on": "2023-06-21T17:18:53.8703087Z",
  "_links": {
    "self": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q"
    },
    "actions": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/actions"
    },
    "capture": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/captures"
    },
    "void": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/voids"
    },
    "authorizations": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/authorizations"
    }
  }
}
```

---

## Extend an authorization's validity period

You can perform an incremental authorization to increase the amount of time you have to capture the payment before it expires.

For Mastercard and Mada payments, you have 30 and 14 days respectively from the date of the original estimated authorization to capture the payment.

For Mastercard, each incremental authorization you perform resets the 30-day expiry period. For Mada cards, you can only extend the validity period once.

> **Note**
>
> For Visa estimated authorizations, the [expiry period](https://www.checkout.com/docs/payments/manage-payments/authorize-a-payment.md#Estimated_authorization_validity_period) cannot be extended.

To increase the authorization's validity period, send a request with the `amount` field set to `0`.

Call the following endpoint with the payment `id` returned in the original authorization's response:

> **Information**
>
> Your base URL's `{prefix}` value is unique to your account and environment. To learn how to retrieve your base URLs for the sandbox and production environments, see [API endpoints](https://www.checkout.com/docs/developer-resources/api/api-endpoints.md).

**Production**

`POST` `https://{prefix}.api.checkout.com/payments/{id}/authorizations`

**Sandbox**

`POST` `https://{prefix}.api.sandbox.checkout.com/payments/{id}/authorizations`

### Request example

```json
{
    "amount": 0,
    "reference": "ORD-5023-4E89",
    "metadata": {
      "partner_id": 123989
    }
}
```

### Response example

```json
{
  "action_id": "act_oqpt7d4wacaexa7aoupddxlvtm",
  "amount": 0,
  "currency": "USD",
  "approved": true,
  "auth_code": "410961",
  "scheme_id": "168679383391401",
  "response_code": "10000",
  "response_summary": "Approved",
  "risk": {
    "flagged": false
  },
  "reference": "ORD-5023-4E89",
  "processed_on": "2023-06-21T17:17:25.4737666Z",
  "processing": {
    "acquirer_transaction_id": "900604935930035384724",
    "retrieval_reference_number": "444143809558"
  },
  "balances": {
    "total_authorized": 100,
    "total_voided": 0,
    "available_to_void": 100,
    "total_captured": 0,
    "available_to_capture": 100,
    "total_refunded": 0,
    "available_to_refund": 0
  },
  "expires_on": "2023-06-21T17:18:53.8703087Z",
  "_links": {
    "self": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q"
    },
    "actions": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/actions"
    },
    "capture": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/captures"
    },
    "void": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/voids"
    },
    "authorizations": {
      "href": "https://{prefix}.api.checkout.com/payments/pay_slonfnum2g7evlg47zhno7ao4q/authorizations"
    }
  }
}
```