When GST registration becomes relevant
GST registration is not just a tax registration. It changes invoicing, pricing, bookkeeping, customer communication, and filing routines.
Founders should track taxable turnover rather than only cash received. Invoices, deferred revenue, cross-border supplies, exempt supplies, and overseas customers can complicate the analysis.
Retrospective and prospective views
IRAS explains GST registration using retrospective and prospective views. The threshold commonly referenced in the guidance is more than $1 million in taxable turnover.
| View | Trigger | Founder action |
|---|---|---|
| Retrospective | Taxable turnover for the relevant past period is more than $1 million | Review historical revenue by taxable supplies, not just bank deposits |
| Prospective before 1 Jul 2025 | Reasonable expectation that taxable turnover will be more than $1 million in the next 12 months | Apply within 30 days after forecast date; registration generally on the 31st day after forecast |
| Prospective on or after 1 Jul 2025 | Reasonable expectation that taxable turnover will be more than $1 million in the next 12 months | Apply within 30 days after forecast date; registration generally 2 months from forecast date |
What changes after GST registration
After registration, the bookkeeping system needs to support GST-ready records. A simple spreadsheet can become risky if tax codes, invoice details, input tax evidence, and filing deadlines are not handled cleanly.
- Issue tax invoices with required details
- Charge GST where applicable
- Track input tax claims and supporting documents
- File GST returns on time
- Review zero-rated, exempt, overseas, and mixed supplies carefully
- Keep customer pricing and cash flow impact visible
Preparation checklist before registering
A startup should prepare before the threshold is crossed. GST-ready bookkeeping is much easier to build before registration becomes urgent.
- Last 12 months of taxable turnover
- Forward revenue forecast and supporting contracts or accepted quotes
- Revenue sources, customer locations, and supply types
- Invoice format and accounting software setup
- Payment gateway, marketplace, and SaaS billing data
- Expense evidence for input tax claims
- Pricing and customer communication plan
This article is general information only and is not tax, legal, pricing, investment, or accounting advice. Check current official guidance and get professional advice for your company facts.