Calculate my tax when I fund my own retirement annuity and the company pays half my Provident fund

How can you calculate your tax when you have a voluntry retirement annuity and a compulsary Provident fund

You must add up all your retirement contributions (provident plus RA) and you can claim up to 27,5% of taxable income as a deduction per month - limited to your actual contributions of course. The annual deduction is limited to R350,000 per year.

I would also like to know what the situation was before the first of March this year regarding the above

Please read our blog on the New Retirement Fund Tax Laws. There is a calculation in there which explains the effect of the new laws (versus the old).