How can I convert the returned value from latestRoundData()?

Question

I've been following a tutorial on chainlink documentation, to get the current price of Matic using MATIC/USD Mumbai Testnet Data feed, the function getLatestPrice() returns 65990700. I read that latestRoundData() returns the value in Wei. Then when I converted it using this website https://polygonscan.com/unitconverter to see how much this value is worth of Matic. I got 0.000000000065485509 Matic.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract PriceConsumerV3 {

    AggregatorV3Interface internal priceFeed;

    /**
     * Network: Mumbai
     * Aggregator: MATIC/USD
     * Address: 0xd0D5e3DB44DE05E9F294BB0a3bEEaF030DE24Ada
     */
    constructor() {
        priceFeed = AggregatorV3Interface(0xd0D5e3DB44DE05E9F294BB0a3bEEaF030DE24Ada);
    }

    /**
     * Returns the latest price
     */
    function getLatestPrice() public view returns (int) {
        (
            /*uint80 roundID*/,
            int price,
            /*uint startedAt*/,
            /*uint timeStamp*/,
            /*uint80 answeredInRound*/
        ) = priceFeed.latestRoundData();
        return price;
    }
}

am I missing something ?

Answer 1

Chainlink USD datafeeds return price data with 8 decimals precision, not 18.

If you want to convert the value to 18 decimals, you can add 10 zeros to the result:

price * 1e10

See the decimals function output on the specified feed contract.