The overhang, explained
Parliament has 120 seats, until it doesn't. When a party wins more electorate seats than its party vote entitles it to, it keeps them all and Parliament grows. That shifts the number a government needs, and in a tight election it can matter.
How it works in four steps
- Two votes. Each voter casts a party vote and an electorate vote. The party vote decides how many of the 120 seats each party is entitled to.
- The threshold. A party shares the seats if it gets 5% of the party vote or wins at least one electorate seat.
- Electorate winners go first. Candidates who win electorates take those seats. List MPs fill the rest of a party's entitlement.
- The overhang. If a party wins more electorates than its entitlement, it keeps them all. Nobody loses a seat, so Parliament has more than 120 members, and the majority needed goes up.
The 2023 example
In 2023 Te Pāti Māori won 6 of the 7 Māori electorates, but its party vote of 3.08% was worth only 4 seats. The 2 extra seats were overhang, so Parliament opened with 122 members and the majority was 62. (A later by-election in Port Waikato brought the House to 123.) The table below is calculated with the same method used here.
| Party | Party vote | Electorates won | Entitled seats | Seats in House |
|---|---|---|---|---|
| National | 38.1% | 44 | 48 | 48 |
| Labour | 26.9% | 17 | 34 | 34 |
| Greens | 11.6% | 3 | 15 | 15 |
| ACT | 8.6% | 1 | 11 | 11 |
| NZ First | 6.1% | 0 | 8 | 8 |
| Te Pāti Māori | 3.1% | 6 | 4 | 6 (+2 overhang) |
Try it yourself
Change the party vote or the electorates each party wins and watch the House size and majority move. This applies the seat-allocation rules to the numbers you enter. It is a calculator, not a forecast.
Why it matters in a close election
Overhang seats raise the majority a government needs, and the party that wins them gets extra MPs without taking seats from anyone else. When the two sides are close in the polls, that can change which side can form a government. Parties have also debated tactics such as asking voters to split their party vote and electorate vote differently. Whether any of that happens is up to voters and shows up only in the final count, so treat anything before 7 November as a calculation, not a prediction.
Questions people ask
What is an overhang seat in New Zealand politics?
An overhang seat happens when a party wins more electorate seats than its share of the party vote entitles it to. It keeps all of them, and Parliament grows beyond 120 seats to make room. In 2023, Te Pāti Māori won 6 electorates on a party vote worth about 4 seats, so there were 2 overhang seats and Parliament had 122 seats.
How many seats are in the New Zealand Parliament?
Parliament has 120 seats by default. Overhang seats can add to that, which also raises the number needed for a majority. With 122 seats, a majority is 62.
What is the 5% threshold?
Under MMP a party gets a share of list seats if it wins 5% of the party vote or wins at least one electorate seat. Parties below 5% with no electorate win get no seats, and their votes do not count towards the seat split.
Poll data: Wikipedia, Opinion polling for the 2026 New Zealand general election (CC BY-SA 4.0), compiled from published polls by 1News–Verian, RNZ–Reid Research, The Post–Freshwater Strategy, Taxpayers' Union–Curia, Roy Morgan and others. 2023 results: Electoral Commission. NZ Business Alliance is non-partisan and does not endorse any party.