You can use this calculator to simulate the result of a New Zealand MMP general election.
Use the main table to adjust the vote share of each party, and the number of electorate seats they would win, press the Calculate button and the make up of your Parliament will be shown below.
The starting values (for both party vote share, and electorates won) are based on the outcome of the 2017 general election. You can change the party vote to the values from one of the five most recent public polls using the Starting Values selector.
You can use the Pick specific electorate outcomes button to change the outcome of individual seats and see how that impacts the result.
Note that the total of the party vote outcome must be 100% or less. The Colmar Brunton poll from 2019-07-24 adds up to over 100%, so will error.
I'm planning some additional features for this. If you have any great ideas of your own, or find any bugs, please send me an email ([email protected]).