According to
Government - Historical Debt Outstanding - Annual 1950 - 1999, the debt at the end of the 1980 fiscal year, on September 30th, 1980, was $907,701,000,000. On September 30th, 1981, it was $997,855,000,000. Averaging it out over the year gives a debt of $246,997,260.27 per day.
Reagan took office 112 days later on January 20th, 1981. The debt on that date could be estimated as $907,701,000,000 plus 112 x $246,997,260.27, or $935,364,693,151.
Bill Clinton was the first president to slow the rate of the accrual of debt after the current out-of-control spending began with the Borrow and Spend Republicans in 1981.
The final amount of the senior Bush debt was $4,174,218,594,232.91 (according to
Debt to the Penny (Daily History Search Application)), and Clinton became president on January 20th, 1993. Bill Clinton saw $1,553,558,144,071.73 added to the national debt during the eight years of his presidency.
However, from the start of fiscal year 1994 (7 months after Clinton became president), until the start of fiscal year 2002 (7 months after Bush took office), the amount of money paid toward interest on the existing Federal debt was $2,767,282,794,374.59 (
Government - Interest Expense on the Debt Outstanding).
Therefore, no amount of the national debt is attributable to Bill Clinton - his policies of higher taxes and reduced spending actually simultaneously reduced the debt and brought about the strongest economy since World War II, despite the fiscal disaster left in the wake of Reagan and the first Bush.
The debt was at $5,727,776,738,304.64 on January 19th, 2001, the last business day before George W. Bush took the office of president.
The debt was at $10,628,881,485,510.23 on January 16th, 2009, the last business day before Barack H. Obama became president.
ReaganBushDebt.org Calculation Details