Warren Buffett said Monday the Republican health-care bill would slash his taxes.

"It was huge what they did on cutting taxes for the rich" in the GOP's measure to replace Obamacare, Buffett said Monday on CNBC's "Squawk Box." "If there's one clear-cut message that comes out of that bill it is we're going to cut the hell out of income taxes for the rich on investment income."

The GOP bill, which was approved by the House last week and heads to the Senate, would eliminate an Affordable Care Act tax imposed on the wealthy that, in part, pays for health-care coverage for Americans.

The tax cuts are in the House Republican bill, which calls for the repeal a 3.8 percent investment tax, such as capital gains, and a 0.9 percent Medicare payroll tax. Both of those apply to individuals earning $200,000 or more a year and couples earning more than $250,000.

Buffett said his personal tax bill would be 17 percent lower under the GOP health measure — about $680,000 on his tax bill of a "little less than $4 million."

"I've had years when it's been a lot more than $680,000. But I'm $680,000 better off if everything else is equal just because of what happened last week," Buffett said, while pointing out this is all theoretical because the Senate needs to take up the health-care bill and there may be changes from that side of Capitol Hill.