There is a limit on how much you can put into super each year by salary sacrifice. Most people can contribute up to $30,000, including your employer's 9.5% super guarantee contribution. This is called the concessional contributions cap.f you want to sacrifice some of your salary to super you should enter into a formal agreement with your employer. It is best to include the details in your terms of employment. This ensures your employer calculates their 9.5% super guarantee contribution on your original salary.