The buying and selling of Bangladeshi Taka (BDT) against other currencies, such as the US Dollar (USD), is typically conducted through foreign exchange markets. These markets involve financial institutions, such as banks, currency exchange agencies, and online platforms, where individuals and businesses can trade currencies.

When buying or selling a currency, there are two exchange rates involved: the "buy" rate and the "sell" rate. The buy rate represents the amount of foreign currency (such as USD) that you need to pay to acquire a certain amount of BDT, while the sell rate represents the amount of foreign currency you will receive in exchange for a certain amount of BDT.

The exchange rates for currencies are determined by market forces, including supply and demand dynamics. Factors such as interest rates, inflation, economic stability, political events, and market speculation can influence the value of a currency. If there is high demand for a currency, its value may increase, leading to a higher buy rate and a lower sell rate. Conversely, if there is low demand for a currency, its value may decrease, resulting in a lower buy rate and a higher sell rate.

To get the most accurate and up-to-date exchange rates for BDT to USD or any other currency pair, it is recommended to check with reliable financial sources, such as banks, financial websites, or currency exchange agencies. They can provide you with the current rates and any associated fees or charges for buying or selling currencies.