Treasury figures show the US national debt has more than doubled in a decade, reaching a milestone US$40 trillion.

The Congressional Budget Office, CBO, says the US$40.5 trillion, as of August 18, covers all outstanding Treasury bonds, bills and notes.

The rise reflects years of heavy spending under both the Trump and Biden administrations, along with higher interest payments.

In 2016, the national debt stood at just under US$20 trillion.

The CBO had projected overall borrowing would reach US$39.6 trillion dollars by the end of fiscal year 2026.

The faster-than-expected rise has sharpened concerns about how quickly the government’s borrowing needs are growing and what that means for future interest costs.

The CBO says the US is nearing its US$41.1 trillion debt ceiling. It says debt is projected to climb to about US$64 trillion by 2036.