Why is my estimated Tax refund lower when I enter my two incomes (One of which does NOT claim the tax free threshhold?)?

I live and work in AUS: Income 1: $42310 gross with tax of $9266 so far Income 2: $11078 gross with tax of $2635 When combined and placed into tax calculator the estimation is that I will receive $2134 back If I just claim enter them separately, I will receive $3487 if it was just income 1, or $2635 if it were... show more I live and work in AUS:

Income 1: $42310 gross with tax of $9266 so far

Income 2: $11078 gross with tax of $2635

When combined and placed into tax calculator the estimation is that I will receive $2134 back

If I just claim enter them separately, I will receive $3487 if it was just income 1, or $2635 if it were just income 2, this is significantly more. I understand the more you earn, the less you receive, but I figured I would at least be refunded more as my second income is at a high tax rate.

I am absolutely useless at this and would love someone to help explain haha
3 answers 3