"The last seven or eight years have averaged 2 percent roughly," he pointed out in an interview with CNBC's Becky Quick that aired on Friday. "It's stronger than that right now."
But he said, "There's no way to calibrate it. They [the government] have their own problems with seasonal adjustments in the first quarter."
The Commerce Department last week reported in its initial look at first-quarter U.S. economic activity that growth slowed to a 2.3 percent annual rate. The economy grew at a 2.9 percent pace in the fourth quarter.
Economists expect growth will accelerate in the second quarter as households start to feel the impact of the Trump administration's $1.5 trillion income tax package on their paychecks. The tax cuts came into effect in January. A growth rate of 3 percent has been a goal of President Donald Trump and his economic team.
"The 'Berkshire Hathaway index' of business activity," Buffett said tongue-and-cheek, "is stronger than it's been. It's been improving year after year after the financial panic."
Buffett gets a rare birdseye view of the economy because of the wide range of businesses that Berkshire owns. He spoke to CNBC Thursday evening from Omaha, Nebraska, where tens of thousands of Berkshire shareholders will be gathering this weekend for Saturday's annual meeting.
Buffett also revealed to CNBC that in the first quarter, Buffett's Berkshire Hathaway bought an astounding 75 million shares of Apple. That adds to the 165.3 million shares Berkshire already owned at the end of 2017.
"It's an amazing business," Buffett said of Apple. "You can put all of their products on a dining room table."
— Reuters contributed to this report.