The real rate of growth of the US economy is, on average, about 2.5 % annually. The Chinese economy grows, on average, at a rate of 8.5 %. According to World Bank data in 2011 the GDP of the United States and China was 14.99 and 7.31 trillion dollar, respectively. How long will it take for China to reach the current size of the US economy? Is it possible for China to overtake the United States in 21 century?