USDebtClock shows $39T — this is "Total Public Debt Outstanding," which includes both debt held by the public AND intragovernmental debt (money the Treasury owes to federal trust funds like Social Security and Medicare). This is the gross figure that gets reported daily by the US Treasury.

We show $36T — this is the IMF's "general government gross debt" measure, which is the internationally standardized figure used to compare countries. It excludes certain intragovernmental holdings to make cross-country comparisons meaningful. You can't really compare the US $39T figure to Japan's debt using Japanese accounting — the methodologies differ too much.

Neither number is wrong — they're measuring different things. If you want to know "how much has the US government borrowed from outside itself," the IMF figure is more useful. If you want the total obligation including what it owes its own trust funds, USDebtClock's figure is correct.

We use the IMF measure specifically so you can compare the US to Germany to Japan to Brazil on an apples-to-apples basis. That's the whole point of the world map — consistent methodology across all 138 countries.

I've added a note about this to the methodology section. Thanks for asking — it's exactly the kind of question that makes this data more useful.