Warren Buffett: Economy 'not bad' but 'not booming'

Warren Buffett: Never go below $20B cash
Warren Buffett: Bought IBM in 1st & 3rd quarter
Warren Buffett talks Phillips 66 stake

Berkshire Hathaway's Warren Buffett said Tuesday the U.S. economy is growing at about 2 percent, a rate he characterized as not bad.

"We're still on that path we've been on for six years," the chairman and CEO of Berkshire Hathaway said on CNBC's "Squawk Alley." "That's not a bad rate, but it's not a booming rate, either."

Buffett made his remarks as investors around the world ponder whether or not the Federal Reserve will move forward on raising interest rates, given the recent volatility in financial markets.

Read More Check out the stocks that are on Buffett's radar

"If our rates got substantially higher than Europe's, I don't think that would be good for exports in this country," Buffett said. "In economics, you can never do one thing. There is always a 'then what' and I think the 'then what' of raising rates while Europe's trying to keep them low could have some consequences down the line."

Buffett also said he bought more shares of IBM in the first and third quarters. Its stock price was up nearly 2 percent after the interview aired.

The previous time the Oracle of Omaha spoke with CNBC in early August, he discussed the conglomerate's $37.2 billion acquisition of Precision Castparts, an aircraft equipment maker, saying "This a very high multiple for us to pay."

Berkshire offered $235 per share for the company, a premium of 21.2 percent to Precision's Aug. 10 close of $193.88.

On Tuesday, Buffett noted Berkshire would probably spend $32 billion in the next four to five months, largely on the Precision Castparts deal, but that the firm would stick to its spending principles.

"I still got money to buy. I'll never go below $20 billion in cash," he said.

He also discussed why Berkshire took a $4.48 billion stake in oil refiner Phillips 66, after having traded out of the stock in 2013. "We were able to do that on a tax-advantage basis. We didn't trade them because we didn't like the stock," Buffett said.

"I had always intended on coming back in, assuming that the price was right."

Phillips 66 in the last 10 days

—CNBC's Matthew J. Belvedere contributed to this report.

This story has been updated to make clear that Buffett's plans to spend $32 billion in the coming months are part of his pre-existing spending plans and not a new investment.