Tax for temporary employees

I am a temporary employee with three months contract in a municipality. I earn R37. 50 per hour and get paid on monthly basis. Last month my employer taxed me 18% on my salary. I worked for 160 hours. Is this the right percentage they used? please advise me on the applicable tax law for temporary employees.

They should be taking off 25% as a temp employee, but if you have over paid your taxes then when you submit your tax return you will receive a tax refund. Please make use of our SARS income tax calculator to work out what taxes were owed.