About how long will it take for Series EE bonds purchased this year to reach face value? In the past it took about seven or eight years. If the new EE take longer, are there other US bonds which will double in value in about a 10 year period? Tom's response Series EE bonds purchased now are guaranteed to reach face value in 20 years. Because the interest rate on these bonds is adjusted every six months, they could actually reach face value sooner than that if interest rates go up enough. Doubling in value in 20 years is the equivalent of a 3.5% interest rate. Right now these bonds are actually paying less than that. The Savings-Bonds-Alert.com web site has complete information on Savings Bond Interest Rates. To double in value in 10 years, you'd need an interest rate of just under 7.2%. There aren't any low-risk investments currently paying that high a rate. Click here to visit the premier independent web site for U.S. Savings Bond owners.