About This Site
What is the Dai Price?
Dai is a decentralized stablecoin that has a target price of 1 USD.   It has a soft peg, so one Dai may be worth slightly more or slightly less than 1 USD at a given point in time.   This site gives an estimate of the Dai - USD price over time.
How is the Dai-USD price calculated?
If there were large DAI-USD markets, it would be easy to calculate the Dai-USD price.   Coinbase has a Dai-USDC market that is effectively a USD market since USDC can be converted directly to USD on Coinbase with no fee.   This market is tracked on the dashboard as "DAI-USD".   However, the volume of this market is small.   If others form, they will be added.
The largest Dai trading volumes are against ETH.   There are also large ETH-USD markets.   Therefore, if you know the DAI-ETH price and ETH-USD price, you can estimate the DAI-USD price from these values.
How is the DAI-ETH-USD price calculated?
First, the DAI-ETH price is determined from the best price offered on decentralized exchanges.   We do not track DAI-ETH prices on centralized exchanges (because who trusts them?).   We use the algorithm from dexindex.io to find the best price but we also include the price on oasisdex(eth2dai) , one of the biggest decentralized DAI-ETH exchanges.
The following Dexes are queried every minute for the best DAI/ETH price
Uniswap, Eth2dai (oasis), Kyber, Air Swap, DDEX, Radar Relay, Ethfinex, and Bancor
Next we calculate the ETH-USD price.   This is a volume-weighted average price from centralized exchanges that either have 1) direct ETH-USD markets or 2) allow US customers to freely trade ETH for USDC (which can be converted to USD on Coinbase).   Right now the biggest ones are Coinbase and Binance (todo: add Kraken).   One complication is that the largest ETH market on Binance is ETH-USDT.   USDT is a centralized stablecoin that trades at a discount to USDC since it is not directly convertible to USD.   Therefore, we include this market in the ETH price, but adjust the value based on the USDT/USDC market.
The following exchanges are queried every minute for the ETH/USDprice
Coinbase ETH-USD, Binance ETH-USDC, Binance ETH-USDT, Binance USDT/USDC
The Dai-ETH-USD price is then calculated as the:
best DAI-ETH price / volume weighted average ETH-USD price
What influences the Dai-USD price?
We track both the ETH-USD price and the total Dai supply as these may influence the DAI-USD price.   You can toggle these on the main overview graph.
What does the %Volatility Graph show?
The data shown is the percent coefficient of variation for three trading pairs: Dai-USD, ETH-USD, and Euro-USD. Coefficient of variation is the standard deviation / mean and is useful for comparing volatility in data when the means are different.   For each pair, the data is based on hourly quotes for each 24 hour period.   The Euro is provided as a reference point for a low volatility, stable currency that trades freely against the USD.   DAI-USD volatility is based off the DAI-ETH-USD feed