The most common surprise for first-time importers is the gap between the tariff rate they looked up and the duty their broker quotes. Neither number is wrong — India's import duty is a cascade in which each component is calculated on a base that includes the one before it. Once you see the stack, every duty figure becomes checkable.
What Is the Duty Calculated On?
Everything starts from the Assessable Value (AV): broadly, the cost of the goods plus international freight plus insurance — the CIF value, converted to rupees at the customs exchange rate notified by CBIC (which is fixed fortnightly and differs from the live market rate). Getting the AV right matters more than any rate, because every duty in the stack multiplies it.
The Three Core Components
- Basic Customs Duty (BCD) — the rate set by your product's HSN classification in the Customs Tariff. This is the number people usually mean by "the duty rate".
- Social Welfare Surcharge (SWS) — 10% calculated on the BCD, not on the goods' value.
- IGST — the GST rate for your product (commonly 5%, 12%, 18% or 28%), calculated on AV + BCD + SWS.
A Worked Example
Take a consignment with an Assessable Value of ₹1,00,000 and a BCD rate of 20%, IGST 18%:
| Component | Calculated on | Rate | Amount |
|---|---|---|---|
| Assessable Value (CIF) | — | — | ₹1,00,000 |
| Basic Customs Duty | ₹1,00,000 | 20% | ₹20,000 |
| Social Welfare Surcharge | ₹20,000 (the BCD) | 10% | ₹2,000 |
| IGST | ₹1,22,000 (AV + BCD + SWS) | 18% | ₹21,960 |
| Total duty payable | — | 43.96% | ₹43,960 |
A 20% tariff rate, an 18% GST rate — and a 43.96% total outflow at the port. That is the stack at work. Certain goods add further layers: GST Compensation Cess (motor vehicles, aerated drinks, tobacco), Agriculture Infrastructure and Development Cess (AIDC) on specified items, and anti-dumping or safeguard duties where notified against particular products and origins.
Is IGST Really a Cost?
Usually not — and this changes import economics completely. A GST-registered importer claims the IGST paid at import as input tax credit, exactly like GST on a domestic purchase. In the example above, ₹21,960 of the ₹43,960 is recoverable; the true cost layer is the BCD and SWS, ₹22,000. IGST at import is a cash-flow question, not a margin question — plan working capital for it, but do not price your product as if it were sunk cost.
Can a Free Trade Agreement Reduce the Duty?
If your goods originate in a country holding an FTA with India, preferential BCD rates — often nil — may apply. Claiming them requires a valid Certificate of Origin and, under the CAROTAR 2020 rules, the importer must hold origin information and exercise due diligence; customs can and does question weak claims. With India's newer agreements opening more corridors, FTA checking belongs in every landed-cost calculation, not as an afterthought.
Where Do Importers Get This Wrong?
- Quoting BCD as the whole duty — and under-budgeting by half
- Wrong HSN classification — the rate follows the code; a wrong code means differential duty, interest and penalties when reassessed
- Using the market exchange rate — customs applies the CBIC-notified rate
- Ignoring cesses — on the goods that attract them, they are not optional
We built a free duty estimator that runs this exact stack for you, alongside CBM and chargeable-weight calculators. For a classification opinion or a landed-cost workup on a real consignment, our customs broking desk does this daily.
Duty Is Not the Whole Landed Cost
The stack above is the statutory outflow — the landed cost that should drive your pricing adds the commercial layer on top: international freight and insurance (already inside the AV, but a real cash cost), port and terminal handling, CFS charges for sea cargo, the customs broker's agency fee, inland transport to your warehouse, and bank charges on the remittance. Demurrage and detention sit in this list as risk rather than certainty — a consignment that clears in three days pays none; one held for a classification query can see storage charges outrun the agency fee many times over. Importers who budget only the duty stack routinely under-cost a consignment by 5–10% of CIF.
Where These Numbers Appear on the Bill of Entry
Every figure in this article is printed on the Bill of Entry your broker files: the assessable value, the exchange-rate notification applied, and each duty head calculated line by line. Two habits worth forming. First, reconcile the broker's pre-filing checklist against the final BOE — they should match to the rupee, and a professional broker shares both. Second, preserve the BOE and duty-payment challans: for GST-registered importers, the IGST credit flows from ICEGATE into your GSTR-2B, and the BOE is the document that supports it in any scrutiny.
Frequently Asked Questions
Why is my total duty higher than the tariff rate?
Because the tariff rate is only the BCD. Social Welfare Surcharge is added on the BCD, and IGST is then charged on the value plus both duties — so the effective rate on your money is always higher than the headline rate.
Can I claim back any import duty?
IGST (and Compensation Cess, where it applies) is creditable as input tax credit for GST-registered businesses. BCD, SWS and AIDC are final costs and cannot be claimed back in the normal course.
Which exchange rate applies to my import?
The customs exchange rate notified by CBIC, fixed fortnightly — not the interbank or card rate on the day. The notified rate is applied to convert your invoice value for duty calculation.
How do I find the duty rate for my product?
Through its HSN classification in the Customs Tariff, then checking for FTA preferential rates, cesses and anti-dumping notifications against that code and origin. Classification is the step worth professional eyes — every other number follows from it.