Key takeaways
What this article covers, in order:
- How to calculate GST on imported goods
- Key dates and limits to remember
- Common mistakes to avoid
- How HelloBooks helps
- Frequently asked questions
Many people search how to calculate GST on imported goods — imported goods attract IGST at customs, calculated on the assessable value plus duty. Follow these steps.
How to calculate GST on imported goods
- Identify the taxable value for imported goods and the applicable GST rate for its HSN or SAC code.
- For a GST-exclusive price: GST amount = taxable value × rate ÷ 100.
- For a GST-inclusive (MRP) price: GST = price × rate ÷ (100 + rate).
- Split the GST into CGST + SGST within the state, or treat it as IGST across states.
- Record the figures so your invoice, GSTR-1 and GSTR-3B all agree.
Key dates and limits to remember
- GSTR-1 (outward supplies): 11th of the next month, or quarterly under the QRMP scheme.
- GSTR-3B (summary and tax payment): 20th of the next month, or 22nd/24th quarterly under QRMP.
- CMP-08 (composition dealers): 18th of the month after each quarter.
- GSTR-9 (annual return): 31 December of the following financial year.
Filing late costs a late fee of ₹50 per day (₹20 per day for a nil return), subject to a cap, plus interest at 18% per annum on any tax paid late — which is exactly why a reminder-driven filing routine pays for itself.
Common mistakes to avoid
- Applying the rate to a GST-inclusive price without backing the tax out first.
- Forgetting cess on items like cars and tobacco.
- Using an outdated rate — slabs changed effective 22 September 2025.
How HelloBooks helps
HelloBooks is built for exactly this kind of GST work. HelloBooks is free GST accounting software for Indian businesses: you can raise GST-compliant invoices with the correct HSN or SAC code, track input tax credit against your GSTR-2B, and file unlimited GSTR-1 and GSTR-3B returns from one dashboard.
- GST-ready invoicing with automatic CGST / SGST / IGST split and HSN or SAC codes.
- GSTR-2B reconciliation so you only claim the input tax credit you are actually entitled to.
- GSTR-1 and GSTR-3B filing free, with GSTR-9 generated ready to file and e-invoicing on higher plans.
- Due-date reminders so a late fee never catches you by surprise.
Thousands of founders, freelancers and accountants in India run their books on HelloBooks — you can start free, with no credit card.
Frequently asked questions
Can I calculate GST on imported goods myself without a CA?
Yes. The process is online and self-service, and software like HelloBooks guides you through it. Many small businesses do it themselves; a CA is optional for complex cases.
What does it cost?
The government charges no fee for registration or return filing on the portal. You only pay if you use a professional or paid software — and GSTR-1 and GSTR-3B filing is free in HelloBooks.
What happens if I miss the deadline?
Filing late costs a late fee of ₹50 per day (₹20 per day for a nil return), subject to a cap, plus interest at 18% per annum on any tax paid late — which is exactly why a reminder-driven filing routine pays for itself.
