> For the complete documentation index, see [llms.txt](https://sandcastle.gitbook.io/sand-castle-finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sandcastle.gitbook.io/sand-castle-finance/lending/lending-pool-fees.md).

# Lending Pool Fees

There are three total fees for every lending pool.

* Interest Rates
* Swap Fees
* Flash Fees

## Interest Rates

Interest Rates can be entered as a custom graph created in our website. An example is below.

<figure><img src="https://469071036-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FzzwZW3qbBItRfbS9O1tu%2Fuploads%2FFnROD2LAt6WgaQCkgdId%2F30ee4250-6a4c-461e-ae23-d80170e735ac.png?alt=media&amp;token=a9a654ee-1750-4b16-8967-8459c9b37dfd" alt="" width="563"><figcaption><p>Interest Rate vs. Utilization graph showing a random graph</p></figcaption></figure>

The interest rate curve here is used to determine the interest that is charged to the borrower for the loan. The interest rate is effectively a percentage of the provided capital that is charged to the lender every year. The interest does NOT get compounded.

**Example:** A user borrows $100 from a lender with a 10% interest rate. SandCastle would effectively add $10 in debt to the user's position every year.&#x20;

## Swap Fees

*These fees only apply to V3 positions not regular loans or flash loans.*

A Swap fee is essentially a percentage of the total amount of swap fees that a user receives. So a swap fee of 10% would mean that the lender receives 10% of the fee income that a user gets. Note that this does not account for rewards from systems like [Merkle](https://merkl.angle.money/?times=active%2Cfuture%2C\&phrase=\&chains=).

**Example:** If the total amount of swap fees collected by the user is $100, and the swap fee of the lender is 10% then the fees collected by the lender is $10. So the user would end up with $90 and the lender with $10.

## Flash Fees

A user can set a fee for flash loans. The flash fee is how much of the flash loan the lender receives as a fee.&#x20;

**Example:** If a user uses a flash loan to acquire $100 and the flash fee is 1.5%. Then, the fee collected by the lender is $1.5. Essentially  the user must pay $1.5 in fees to acquire $100 in a flash loan.