The exchange rate stability is important for economic development in a nation, specially in balance of trade. So, before the study do balance of trade estimation, it's need to measure exchange rate fluctuation. This study use ARCH and GARCH to measure them.In fact, the exchange rate has ARCH and GARCH effect. In another word, exchange rate fluctuation influenced by current and previous exchange rate fluctuation and it's tend persistent. The study used ECM (Error Correction Model) estimation to determine balance of trade. There are three independent variables in this estimation, that is exchnage rate, Indonesia GDP (Gross Domestic Product) and world GDP.The result, exchange rate is not significant both short and long term. But Indonesia GDP and world GDP are positif significant to balance of trade both short and long term.