What Is a Two-Thirds Majority Vote?

A two-thirds majority vote means at least two thirds of the required base in a meeting support a motion. It is a type of supermajority used when an ordinary simple majority is considered too low a threshold for high-impact decisions. Many constitutions, byelaws and standing orders specify when this higher threshold applies to ensure broad consent rather than a narrow win.

When is it used?

Bodies often require two thirds for decisions that change rights or rules or curtail debate, for example:

• Amending governing documents or standing orders
• Limiting or closing debate, suspending rules or expelling members
• Approving significant financial commitments or structural changes

The rationale is to protect minority interests and to signal that sensitive and impactful actions carry strong support.

How do you calculate it?

The rule of thumb is simple: calculate two thirds of the required base and round up to the next whole vote. If exactly two thirds is not a whole number, you still need the next whole number.

Quick examples (two thirds, rounded up):

• 30 votes cast means 20 in favour are needed
• 25 votes cast means 17 in favour are needed (two thirds is 16.66)
• 12 members present means 8 are needed

State the number required before taking the vote so everyone understands the bar.

What is “the required base”?

Your rules determine which base to use when considering a two-thirds majority. Common formulations include:

Base	How to achieve a two-thirds majority
Two thirds of votes cast	Counts only ayes and noes. Abstentions do not affect the denominator.
Two thirds of members present and voting	Another way of saying votes cast.
Two thirds of members present	Abstentions count in the denominator, making the bar higher.
Two thirds of the entire membership	Hardest to reach and usually reserved for major constitutional changes.

Always follow the exact wording in your constitution or standing orders.

Quorum and eligibility

You must have a valid quorum before applying any threshold and only eligible voters may be counted in the base. Ex officio members are usually eligible unless restricted by conflict-of-interest rules.

Requirements for two-thirds often sit in your statutes, articles or byelaws, with detailed voting procedures in standing orders. Where there is a conflict, the law overrides your byelaws and bylaws override custom. Secret ballots, roll-calls and electronic voting are all acceptable if permitted by your rules.

Common pitfalls

• Using the wrong base or forgetting to round up
• Treating “present” as “in favour,” especially where abstentions are common
• Failing to announce the threshold, which invites disputes after the fact

Best practice for chairs and secretaries

• State the threshold, the base and the exact number of votes required before the vote
• Use a counted vote for high-stakes items
• Record the totals, the threshold and whether the motion passed in the meeting minutes.