You may have been assessed as a non-tax resident, where the overall tax rate tends to be higher. You can check if you qualify to be a Singapore tax resident, and if you do, you may file an amendment using the 'Amend Tax Bill' digital service at myTax Portal. Alternatively, you can email/post the completed Request for Tax Reassessment (DOC, 203KB) form to us. Your income tax balance must be settled by the due date regardless of any amendment request. Any credit balance that arises from the review of your assessment will be automatically refunded within 30 days.

This information is sourced from IRAS