WASHINGTON — The Senate Democratic and Republican leaders on Tuesday reached an agreement on legislation to extend subsidized federal student loans, adding bipartisan pressure to House Republicans to come along before rates double July 1.

The $6.7 billion agreement would extend the current 3.4 percent rate on Stafford loans for one year, with about $700 million extra for deficit reduction, according to Senate leadership aides. The bulk of that — $5.5 billion — would come from two pension measures. One would change how private pension interest payments are calculated, smoothing the fluctuations for businesses even as the total cost rises slightly. The other would come from higher premiums for companies participating in the Pension Benefit Guaranty Corporation.

Another $1.2 billion would come from limiting how long a student could receive Stafford loans to 150 percent of the average time it takes to complete a degree. Currently there are no limits.

“We’re pleased that the Senate has reached a deal to keep rates low and continue offering hard-working students a fair shot at affordable education,” said the White House press secretary, Jay Carney.