Computed by stonks: nominal total public debt outstanding (series us-national-debt, Treasury Debt to the Penny) deflated by US CPI-U (series us-cpi) to constant 2025 dollars. Real value = nominal × (2025 average CPI ÷ CPI at or before the observation date), both monthly, step-aligned (never interpolated). Fixed 2025 base year, so the series does not re-vintage on every new CPI release.