To convert USD to GBP, multiply the value of USD by the current exchange rate to receive the GBP value. As of September 17, 2015, the current exchange rate is 1 U.S. Dollars to 0.6449 British Pounds. However, the rates can vary by the minute.
Although the exchange market between the British Pound and American USD can fluctuate by the minute, the rate has remained at roughly 1USD to 0.6GBP over the past five years. The daily average on September 20, 2010 was 1 USD to 0.638, and the highest peak since then, to date, was on August 19, 2015 at 1 USD to 0.676 GBP.