The federal government chalked up a record $202.8 billion budget deficit in the fiscal year that ended Sept. 30, the Treasury Department reported yesterday. There was another $9.1 billion deficit in so-called off-budget federal programs, raising the total deficit to $211.9 billion.

The previous record for the on-budget deficit was $195.4 billion set in fiscal 1983. Last year's on-budget deficit was $175.3 billion.

Total outlays in fiscal 1985 were $945.9 billion, up nearly $100 billion, or 11 percent, from the previous year. Receipts were $734 billion, a 10.1 percent increase, the department said.

That combination of outlays and receipts meant that the government had to borrow more than $1 for every $5 it spent. It borrowed $202.6 billion from the public, and reductions in its cash balances and other steps covered the remainder.

The cumulative total deficit for the four full fiscal years of the Reagan administration, 1982-85, was $732.9 billion.

The 1985 borrowing pushed the federal debt to the $1.827 trillion mark. This year's deficit, estimated by private forecasters also to be close to $220 billion, will mean the debt will be more than $2 trillion at the end of the year.

Social Security and Medicare outlays were the largest item in the budget at $254.4 billion. National defense spending was close behind at $251.5 billion.

The third-largest outlay item was net interest on the debt, which came to $129.1 billion. That figure was about $400 million lower than expected earlier because of the Treasury's inability to issue new securities last month when it bumped up against the statutory limit on the debt, an increase in which still is being debated in Congress.