> For the complete documentation index, see [llms.txt](https://support.caspen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.caspen.com/using-caspen/billing/payments/apply-an-existing-payment-to-an-invoice.md).

# Apply an existing payment to an invoice

## **Overview**

If a client has made a payment that has not yet been used, you can apply it to an invoice once the invoice is **finalized**.

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## **Apply an existing payment**

To apply an existing unallocated payment:

1. Go to **Billing** → **Invoices** and open the invoice (Actions → View, or click the invoice number).
2. Click **Pay invoice** → **Existing payment.**

<figure><img src="/files/0M735yIDYnP73RGGVo0U" alt=""><figcaption></figcaption></figure>

A list of the client's **unallocated payments** will appear.

3. Enter the amount you want to apply.
4. Click **Apply**.

<figure><img src="/files/V0RuxgZ8PXoeOvYAeX5C" alt="" width="481"><figcaption></figcaption></figure>

The applied amount will appear under the **Payments** section of the invoice.

<figure><img src="/files/U6RrCpzS9fMwiTYHLisP" alt=""><figcaption><p>The invoice’s Payments section shows the applied payment and the allocation number.</p></figcaption></figure>

The **Payments** section shows the payment and the allocation number.

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## How allocations work

When a payment is applied to an invoice:

* The invoice displays the payment with an allocation number
* Clicking the allocation number opens the **Allocation** screen
* From the Allocation screen, click **Allocated from payment** number to open the original payment record

The Allocation screen shows:

<figure><img src="/files/VT2Znipddc2Wfrzy6HBg" alt=""><figcaption><p>The Allocation screen displays the allocated amount, allocated from payment, and allocated to invoice.</p></figcaption></figure>

* **Allocated amount** (how much was applied)
* **Allocated from payment** (the payment the money came from)
* **Allocated to invoice** (the invoice the money was applied to)

In the payment record:

<figure><img src="/files/klo1de5OgqgWUFbztL59" alt=""><figcaption><p><em>The payment record shows the amount marked as <strong>Allocated</strong> and lists the invoices it was applied to.</em></p></figcaption></figure>

* The payment shows an **Allocated** amount
* The **invoices** that received the payment are listed
* The payment and invoice link to each other for easy tracking

This is especially useful when:

* One payment is split across multiple invoices
* Reviewing which invoices were paid using a prepayment or bulk payment

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## **How to unlink an allocation**

Payment allocations can only be removed from the **Allocation** screen.

To unlink an allocation:

1. Click the **allocation number** on the invoice.
2. On the Allocation screen, click **Delete**.

The allocation will be removed, and the amount will return to **Unallocated** in the payment record.