Using those calculators is your best bet, going through each room basically and listing what you have and what it is worth. Nothing worse than under-estimating - I remember a few years ago my neighbours had a kitchen fire - you don't realise how much stuff that isn't directly burned is affected like curtains, bedding, tv's computers etc because of the ash. Anyway they used their WHOLE contents insurance getting everything replaced and repaired and were lucky the entire house didn't go up.

Thanks for the reminder I think we need to update ours too! We shopped around quite a bit but ended up with CBA because it is linked in with our home loan, but I am with Allianz for my cars and find them very competitive.

Good luck!