The increase was driven by speculation that the Federal Reserve would reduce its $85 billion-a-month bond purchases, which have helped keep long-term interest rates low.
Deeming the economy to be gaining strength, the Fed announced in December and January and again on Wednesday that it was reducing its monthly bond purchases.
The Fed said after its latest two-day policy meeting that even after it raises short-term interest rates, the job market strengthens and inflation rises, the central bank expects its benchmark short-term rate to stay unusually low.
Fed Chair Janet Yellen stressed that with the job market still weak, the Fed intends to keep short-term rates near zero for a "considerable" time and would raise them only gradually. Yellen also suggested that the Fed could start raising rates six months after it halts its monthly bond purchases, which most economists expect by year's end. That means short-term rates could rise by mid-2015.
The National Association of Realtors reported Thursday that sales of U.S. existing homes slipped in February, the sixth decline in seven months as severe winter weather, rising prices and a tight supply of homes discouraged buyers.
Still, there were some signs that the market could pick up in the coming months. Sales improved in the South and West, where weather was less of a factor. And more people decided to sell, boosting the supply of available homes.
To calculate average mortgage rates, Freddie Mac surveys lenders across the country between Monday and Wednesday each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.
The average fee for a 30-year mortgage was unchanged at 0.6 point. The fee for a 15-year loan also held steady at 0.6 point.
The average rate on a one-year adjustable-rate mortgage edged up to 2.49 percent from 2.48 percent. The average fee remained at 0.4 point.
The average rate on a five-year adjustable mortgage fell to 3.02 percent from 3.09 percent. The fee was unchanged at 0.4 point.