You may contribute any amount to your SRS account up to your SRS contribution cap.
Your SRS contribution cap is determined by multiplying the appropriate SRS contribution rate by an absolute income base.
SRS contribution rate
The SRS contribution rate for Singaporeans and Singapore Permanent Residents (SPRs) is 15% while the SRS contribution rate for foreigners is 35% in view of the fact that they do not enjoy tax relief from CPF contributions. If you are a foreigner, you are required to give a written declaration of your foreign status for the calculation of your SRS contribution cap. You must make such a declaration on an annual basis for the SRS operator to calculate your SRS contribution cap.
From 1 Jan 2016, the absolute income base is $102,000.
This works out to a contribution cap of $15,300 per annum for Singaporeans and SPRs, and $35,700 for foreigners.
If a person is a non-PR in 2001 but is a PR in 2002, his SRS contribution cap in 2002 should be computed at the rate of 15%, which is the rate applicable to a PR.