Price of petrol + Big Mac + Bank interest rate in Australia December 2025

Welcome to my updated monthly report on key financial figures for Australia. I am doing this to keep historical notes through my life. These figures reported are what I see at the various places and an aggregate.

The price of petrol I paid during December 2025 probably averaged $1.65 for unleaded 91 Octane. Add up to 15c for 95 or 25c for 98.  It’s relative of course due to fluctuation.

The 1st week was 2.29 dropping to 1.60 to the 2nd to last week but literally jumped to $2.20 at the end of the month! Localised price increase, presumably because it was Christmas and New Years public holiday. 

The price of diesel was around $1.90 the last time time looked and this the price does not fluctuate much compared to unleaded. Adblue was priced at about $1.90 per litre.

Following the developments during December in the US market regarding tariffs : Tariffs and continual high inflation are no longer news worthy as other distractions take hold. The latest (It happened just before this update) being the removal of the Venezuelan president which is disturbing since that’s how larger wars start. Lots of good and bad come to mind hope it works out for the better. 

The price of a Big Mac in December 2025 now averages $8.40. The price for the burger alone does vary from store to store based on location! This time it was the usual shopping centre location. The medium sized meal deal which included fries and a drink costs about $13.55 and the large option was $14.45 as per my monthly visit. As always this is not a fixed price as McDonald’s has a very active app and promotional pricing and freebie schedule.

The RBA – Reverse Bank of Australia the country’s central bank kept the interest rate at 3.60 % 
The variable home loan interest rate range in December 2025 in Australia was : 4.5% – 9.5%
The saving interest rate range in December 2025 in Australia was : 0 – 5%
Note that the rates I saw came with conditions or short term promotion periods – very naughty. 

Note that fuel prices also vary according to area, the level of competition and a whole heap of other factors like shopping discounts, wars, world wide economics and so forth, however unreasonable high prices (relative to crude oil prices) is greed. Also note that the Octane level I post here represents Australian measurement which is different from those in other countries eg. US.

Apart from the actual prices I paid at the servo the websites I use to research the crude oil pricing are:

Australian Institute of Petroleum (Note that they AIP represents the oil companies.)
Index Mundi (Seems independent)