---
# System prepended metadata

title: Swap details

---

# Swap details
Parameters of swap trade

## Short view
### Exchange rate
Token A to Token B exchange rate and vice versa

Swap exchange rate calculated according to specified swap volume

```pool_exchange_rate = token_a_pool_size / token_b_pool_size

constant_product = token_a_pool_size * token_b_pool_size

constant_product will be the same number before and after a trade occurs.

new_token_a_pool_size = token_a_pool_size + token_a_paid

new_token_b_pool_size = constant_product / new_token_a_pool_size

token_b_recieved = token_b_pool_size - new_token_b_pool_size

a_exchange_rate = token_b_recieved / token_a_paid Swap exchange rate 1 TokenA = X TokenB

b_exchange_rate = token_a_paid / token_b_recieved Swap exchange rate 1 TokenB = X TokenA
```

#### SPIKE / NOTE
Currently on async function calculateReserves call we return:
- token_b_recieved
- minimum_token_b_recieved

uniswap-casper-interface/src/contexts/ConfigContext/index.tsx

Line 112 in e544343

 async function calculateReserves(firstTokenSelected, secondTokenSelected, value) { 

## Full view
### Minimum received
Minimum Token B amount user will recieve, before transaction will be reverted.

Minimum recieved amount determinated by slippage settings.

Formula:
```
minimum_token_b_recieved = (token_b_recieved - (token_b_recieved * slippage_tolerance) / 100)
```
### Price impact
What is Price impact? Price impact is the difference between the current market price and the price you will actually pay when performing a swap transaction on a decentralized exchange

price_impact = ( b_exchange_ratec / pool_exchange_rate - 1 ) * 100

### Slippage Tolerance
The maximum difference (in %) between your estimated price and executed price

Used to calculate minimum amount of Token B to recieve before transaction will be reverted

### Protocol fee (% token A)
Router protocol fee represented in Token A

0.3% of total Token A volume of swap transaction
Fee set globally for every token pair (pool) Fee recipients:

0.25% Liquidity providers
0.05% Treasury
protocol_fee = token_a_paid * 0.3 / 100

providers_fee = token_a_paid * 0.25 / 100

treasury_fee = token_a_paid * 0.05 / 100

### Network gas fee
Swap transaction Casper network fee paid in CSPR and prederminated:

Swap + Approve =

Swap =