Microsoft thinks the Federal Communications Commission is vastly undercounting the number of Americans who still don't have access to broadband internet.

In a Monday blog post, the tech giant said it found that 162.8 million people aren't using the internet at broadband speeds. That's a much greater number than the 25 million Americans the FCC estimates don't have access to broadband.

The FCC builds its coverage map, which has been widely criticized as inaccurate, using data that internet service providers report twice a year via what's called Form 477. Microsoft said this form is too broad and that FCC mapping based on census blocks lacks specificity.

"The FCC data is based on census blocks, the smallest unit used by the US Census Bureau -- though in rural areas, these blocks can be quite large," John Kahan, chief data analytics officer at Microsoft, wrote in the blog post. "If broadband access is delivered to a single customer in that block, the entire block is counted as having service."

Broadband coverage maps are used to determine who does and doesn't get funds dedicated to closing the broadband coverage gap. In December, FCC Chairman Ajit Pai said the agency would investigate if carriers have submitted incorrect coverage data.

Microsoft suggested the FCC update Form 477 and use both availability and actual usage data to guide its investments. It also suggested the FCC update its methodology before releasing its next update on broadband coverage.

The FCC didn't immediately respond to a request for comment.