Gary Cohn, director of the National Economic Council, does not expect the White House to get a tax bill in front of Congress until the first two weeks of September.

In a meeting with tech executives on Tuesday, Cohn said the administration is focused on negotiating all the stumbling blocks before then because they don't want "to be negotiating a bill on the floor."

Cohn said President Donald Trump has been very involved in the process, often checking in with him and Treasury Secretary Steven Mnuchin. Trump "could not be more excited about what we're doing. One of us — if not both of us — gets a call every day and sometimes more than one a day, asking us how tax reform is coming," Cohn said.

House Speaker Paul Ryan was less committal in a speech at the American Manufacturing Summit on Tuesday, simply saying Congress would complete tax reform by the end of the year. However, in a CNBC interview Tuesday, Ryan said they "agreed on the timeline."

CNBC's Angelica LaVito contributed to this story.