Mature age worker tax offset, is for Australian residents for tax purposes who are 55 and over and are working.
The tax offset is calculated on the net income that has been derived from working. Working usually requires an effort or skill that can be used to produce an income.
To get the full offset of $500, your income from working must be less than $53,000. From $53,000 to $63,000 the offset is reduced by 5 cents for every $1 over $53,000. Once over $63,000 the offset is reduced to nil.