Bitcoin Forum

For example look at bitpay.com and coinbase.com

Their exchange rates from bitcoin to USD vary by 2-3 dollars. I've looked at other sites too and they vary. BitPay seems to be lower based on the few sites that I looked at.

It depends on the market, not the wallet. The exchange on each one is different.

I recommend you this website https://bitcoinwisdom.com/

As mentioned above, wallets use exchanges as a reference for currency conversion. Each wallet has its own reference.

https://bitcoinaverage.com/ is my personal favorite for reference.

The reason why a site like Bitpay has a lower rate is because the service they offer (convenient fiat conversion for merchants) is priced in.

$2-3 is such a small value that it can even be because of the update speed of their API. the market is changing and they might update the price with delay in the wallet to lower the pressure.

There's no central authority in Bitcoin, so everyone can make its own price. And you're free to select the service you prefer...

It's part of running a business. It's no different when it comes to exchangers and how they run the operation to minimize cost and improve efficiency. Those that have the lowest fee with the best service of course have the advantage.

I  think, all the exchanges having interconnected between them and the rate was determined by the supply of those exchanges and they've to equalize the rates?

i think it's equalized by itself in the sense that the internal demand will adjust itself by viewing the other rate on other exchange, so at the end the volume matter relatively, the demand will be around the same, it is forced to be the same actually...

They get the information from different exchange, which may have different exchange rates. There would always be difference between the value of exchanges. The trade volume is one of the bigger factor, bigger volume difference would result in a higher difference in exchange rate as there are little trade. Many sites uses averages which gives the exchange with larger value more weight compared to an exchange with a lower volume.

the price in different exchangers would equalize because if it doesn't then the volume would quickly shift to the one with the different price and then this volume increase would adjust the price automatically.

Like others have posted above, different websites are pulling the different prices from different sources/exchanges. So don't sweat too much about it. On the top of that, Coinbase is an exchange as well as wallet, so their conversion rate comes from its own trading.

If you install Multibit wallet for example, you would have options to choose from where you want to get your price from. From which exchange, is it in EUR, USD, etc..

This situation is actually have an advantage which you can earn profit, use an Arbitrage (https://en.wikipedia.org/wiki/Arbitrage) technic, you can buy on exchange service which have low rate to buy bitcoin and sell it to exchange which have high rate.

It depends. Some wallets use APIs to pull from third party services, such as BitPay, Bitcoin Average, or even CoinDesk. Some will take the average from several large exchanges. Or some will just take one price from a single exchange. It varies wallet to wallet.

I guess every wallet has the option to change into your preferred exchange need to be showed. So, it's not the fixed one the way they force you to follow a particular exchange.