How to calculate the median weekly personal income?
Something we get asked for a lot here at .id is median weekly personal income.
While it’s not available on our profile.id sites, you can calculate it from the ranged personal income data on the site.
You can find the data here (I’m using the City of West Torrens for this example, my old stomping ground!):
Export the data from the Weekly individual income table into Excel
Once Excel opens, this is what it should look like
The next step is to remove the “Not stated” category, and recalculate the percentages (I’ve also deleted the Greater Adelaide column, so we don’t all get confused) Firstly, recalculate the Total persons aged 15+
Then calculate the new percentages (putting the ‘$’ between the B and the 15 means it will always divide by this cell, even as you drag the formula down)
The next step is to calculate the cumulative percentages as you progress through the income ranges
The formula for the first cell is a bit different, but from the second one you can just drag the same formula down
The next step is to determine in which income range the 50% mark falls. As you can see from the example, the median for West Torrens falls somewhere within the $400-$599 range
Next you need to work out the difference between this range and the one below it
Then calculate the difference between 50% and the same lower income range
Now divide this new value by the one calculated a few steps ago. This value shows how far into the identified income range the median falls
So in the case of West Torrens we can see that the median falls 0.73 of the way through the $400-$599 income range. To work out what that is, multiply the dollar amount in the range (in this case $200) by the proportion you just calculated
Add this amount to the lower amount of the income range (in this case $400)
Now you have your median income!
To access demographic information for communities across Australia, please visit our demographic resource centre.