Congressional Glossary
What is a quorum in Congress?
A quorum is the minimum number of members who must be present to do business: a majority of each chamber, which means 218 of 435 in the House and 51 of 100 in the Senate.
In one sentence
A quorum is the minimum number of members who must be present to do business: a majority of each chamber, which means 218 of 435 in the House and 51 of 100 in the Senate.
Members required: 218 of 435 in the House; 51 of 100 in the Senate
What counts as a quorum
Article I, Section 5 of the Constitution sets the rule in one line: "a Majority of each shall constitute a Quorum to do Business." A majority of the House's 435 seats is 218 members. A majority of the Senate's 100 seats is 51. You can read the clause itself at constitution.congress.gov.
When seats sit vacant, the math shifts. Both chambers count a quorum as a majority of the members actually chosen and sworn, so a House with 432 sitting members needs 217 present, not 218.
What percentage is a quorum
Just over half. A quorum is 50 percent of the chamber plus one member, and no more than that. People often mix it up with the higher bars Congress uses for passing things, like 60 votes for cloture in the Senate or two-thirds to override a veto. Those thresholds decide outcomes. A quorum only decides whether the chamber can act at all.
How a quorum call works
The Senate checks attendance with a quorum call: a clerk reads the roll of senators, name by name. In practice, most Senate quorum calls are not real attendance checks. Leaders use them as an official pause while they work out scheduling or wait for a senator to reach the floor, then call them off by unanimous consent once business resumes. The Senate's own glossary describes the habit (senate.gov).
The House works differently. It presumes a quorum is present unless a member raises a point of order that one is not. When that happens, bells ring through the House office buildings and members record their presence at the electronic voting stations, the same machines they use for a roll-call vote.
Why the quorum rule exists
The Framers wanted to keep a handful of members from passing laws in a near-empty chamber. The same clause also hands each house a tool against the opposite problem: it may "compel the Attendance of absent Members" when too few show up. Walkouts meant to break a quorum have a long history in American legislatures, though in today's Congress the routine quorum call is a far more common sight.
Quorum and real votes
A quorum is about presence, not passage. On April 21, 2026, the House passed the Kari's Law Reporting Act 198 to 5. Only 203 members cast a vote, well short of 218. The result stands anyway: a quorum is presumed unless a member questions it, and a member who skips a vote may still be sitting in the chamber.
Common questions
A quorum is the minimum attendance required to conduct business: a majority of the chamber. That is 218 of the House's 435 members and 51 of the Senate's 100. The requirement comes straight from Article I, Section 5 of the Constitution.
Just over 50 percent. The Constitution sets a quorum at a majority of each chamber, meaning half the members plus one. Higher thresholds, such as 60 votes for cloture or two-thirds for a veto override, apply to passing measures, not to attendance.
A quorum call is how a chamber checks attendance. In the Senate a clerk calls the roll of names; in practice many quorum calls are official pauses while leaders negotiate. In the House, members record their presence by electronic device after a point of order.