# Reading pool price

How to interpret pool data from the on-chain methods

Let's say you wanted to determine the human-readable price of the ETH-USDC pool on mainnet.

These two tokens are:

First, let's determine which token is

`token0`

and which token is `token1`

. We can do this by comparing the integer values of the addresses. In this case, `0x053c91253bc9682c04929ca02ed00b3e423f6710d2ee7e0d5ebb06f3ecf368a8 > 0x049d36570d4e46f48e99674bd3fcc84644ddd6b96f7c741b1562b82f9e004dc7`

, so USDC is `token1`

and ETH is `token0`

.Next, we need to decide which pool to read. Let's use the pool with the 0.05% fee and the 0.1% tick spacing, since it's the most popular ETH/USDC pool. The easiest way to get the fee and tick spacing parameters is to read the URL from the website when you add liquidity to this pool:

https://app.ekubo.org/positions/new?baseCurrency=ETH"eCurrency=USDC&fee=170141183460469235273462165868118016&tickSpacing=1000

The second easiest way is to compute the value. Fee is a 0.128 fixed point number, so to compute the fee, we can do

`floor(0.05% * 2**128)`

. The result is `170141183460469235273462165868118016`

. The tick spacing of `0.01%`

is represented as an exponent of `1.000001`

, so it can be computed as `log base 1.000001 of 1.001`

, which is roughly equal to `1000`

. The extension is `0`

because it is not used for this pool.Input the values into the Core contract on Voyager to read the pool price. If you're following along, you'll get a value that looks like this:

{

"sqrt_ratio": "0x029895c9cbfca44f2c46e6e9b5459b",

"tick": {

"mag": "0x0135566d",

"sign": "0x01"

},

"call_points": {

"after_initialize_pool": "0x00",

"before_swap": "0x00",

"after_swap": "0x00",

"before_update_position": "0x00",

"after_update_position": "0x00"

}

}

Let's compute the price from this result. The value

`sqrt_ratio`

is a `64.128`

fixed point number. To convert it to a price, first divide it by `2**128`

, then square it to get the price. Since USDC is `token1`

, this value is the price of the pool in USDC/ETH. `(0x029895c9cbfca44f2c46e6e9b5459b / 2**128)**2 == `

`1.56914... ×10^-9`

. To adjust for display, we have to account for the decimal difference between the USDC and ETH tokens. Because USDC has 6 decimals and ETH has 18 decimals, we need to scale it up by `10**(18-6)`

to be human readable. `1.56914e-9 * 1e12 == 1.56914e3 == 1569.14 USDC/ETH`

.

Last modified 3mo ago