"For fiscal year 2013, it will cost an estimated $5.9 billion to operate Congress and the rest of the legislative branch. Salaries and benefits alone account for more than $2.5 billion of that sum."1,2
That number has been revised downward for 2013 to $5.64 billion, and is estimated for 2014 to be $5.8 billion.3
I'll look at the revised 2013 numbers for this analysis. Of the $5.64 billion, approximately $1 billion were "reimbursable expenses", leaving $4.585 billion in total direct obligations due to the legislative branch.3
Dividing that $4.585 billion evenly across all 365 days gives an average cost of $12.6 million per day.
However, that analysis may be too simplistic. In 2013, the house is in session 126 days.4 The senate is in session 195 days.5 Some expenses (for example: salary, rent) should be accounted for evenly across all days. Other expenses (for example: communication, advisory services, printing), should be accounted for more heavily on the days in session. This is a very crude division. Communication, printing, etc. can happen on out-of-session days, but I'll assume that it all happens on in-session days. Because of this, my estimates are something like upper bounds on what a single day could cost congress.
Allotting the following lines3 ($2,812 million) across all 365 days evenly results in $7.7 million per day.
- 11.1-13.0 All Personnel Compensation and Benefits: $2,480 million
- 23.1 Rental Payments to GSA: $47 million
- 23.2 Rental Payments to others: $21 million
- 31.0 Equipment: $139 million
- 32.0 Land and Structure: $102 million
- 33.0 Investments and Loans: $2 million
- 41.0 Grants Subsidies and Contributions: $11 million
- 94.0 Financial Transfers: $10 million
Allotting the remaining lines ($1,773 million in costs like supplies and materials, operation, advisory services, printing, communications, transport)3 across only days in session results in an additional 14 million per day (if we divide across the 126 days that the house is in session), or an additional 9 million per day (if we divide across the 195 days that the senate is in session).
In summary:
- Costs per day that are due to expenses spread across the year: $7.7 million
- Additional cost per in-session day: $9-14 million
- Cost per day that the US congress is in session: $16.7 - $21.7 million
References
1. Carolina Miranda. Should we outsource congress?. TIME. July 25, 2012.
2. Object Class Analysis: Budget of the U.S. Government, Fiscal Year 2013. Office of Management and Budget. 2012. p.4
3. Object Class Analysis: Budget of the U.S. Government, Fiscal Year 2014. Office of Management and Budget. 2013. p.4
4. Eric Cantor. House Calendar for the First Session of the 113th Congress. 2012.
5. Dick Durbin and John Cornyn. Tentative Schedule for the First Session of the 113th Congress. 2012.