# Fees

{% hint style="info" %}
EthAnchor is scheduled for deprecation and is to be replaced with xAnchor. It is highly recommended that new integrations are built with [xAnchor](https://docs.anchorprotocol.com/protocol/xanchor) and not with EthAnchor.
{% endhint %}

EthAnchor is built using various blockchain infrastructure that charges fees on their usage. Using EthAnchor incurs fees that are calculated based on the deposit / redeem amount. Fees listed at this section are applied independent of gas spent on Ethereum transactions.

| Operation         | # of Swap Fees | # of Shuttle Fees | # of Terra Tax |
| ----------------- | -------------- | ----------------- | -------------- |
| Deposit           | Once           | Once              | Once           |
| Withdraw (Redeem) | Once           | Once              | Twice          |

## Swap Fees

Operations with non-UST stablecoins are automatically converted to UST via Curve. A **0.04%** fee is applied by Curve on each swap.

In addition to Curve fees, the swap will incur slippage -- the difference between the current market price and the price at which the trade is effectively executed.

## Shuttle Fees

{% hint style="warning" %}
Shuttle ignores transfer requests with a transfer value smaller than **1 UST**.
{% endhint %}

Cross-chain transfers of Terra stablecoins and aTerra tokens between Ethereum and Terra are facilitated with the use of [Shuttle](https://github.com/terra-project/shuttle). Shuttle charges a fee **only** for cross-chain token transfers from Terra to Ethereum, with the fee amount being: 

$$
\text{shuttleFee(transferAmount)}=\text{max} (1,\text{UST},,\text{transferAmount} \cdot 0.25% )
$$

**0.25%** of the transfer amount is charged as Shuttle fees, decreasing with the transfer amount until the fee reaches the 1 UST minimum. Amount received after fees will be: 

$$
\text{receiveAmount} = \text{transferAmount}-\text{shuttleFee}(\text{transferAmount})
$$

Note that this fee will be applied **once** for **both** deposits and withdrawals.

## Terra Blockchain Tax

Terra stablecoin transfers that occur on the Terra blockchain require tax (protocol fee) to be paid. Tax amount is dependent on the transfer amount, represented as: 

$$
\text{terraTax(transferAmount)} = {\text{min}(\text{taxCap}, \text{transferAmount}\cdot\text{taxRate})}
$$

Tax amount increases as the transfer amount increases, until it reaches a cap of 1 TerraSDR (SDT), currently valued at around \~1.42 UST. Terra SDR is a Terra stablecoin pegged to the International Monetary Fund's Special Drawing Rights (SDR) and its value -- along with the tax cap -- may differ as exchange rates vary with time.

EthAnchor is configured to automatically deduct the amount of stablecoins required for tax before making Terra-side transfers. Thus the post-transfer receive amount will be: 

$$
\text{receiveAmount} = \text{transferAmount} - \text{terraTax(receiveAmount)}
$$

Note that this tax fee is applied **once** for deposits and **twice** for withdrawals.