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Published on:

February 24, 2026

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Iron Oxides & Hydroxides: GST Rates & HSN Code 2821

That mismatch usually shows up later. An invoice gets stuck. ITC doesn’t move. Someone notices the rate or code looks different from last month. What should’ve been routine turns into edits, explanations, and backtracking no one planned time for.

If you’ve seen that happen, this will help. We break down HSN Code 2821, confirm the GST rate that applies today, and explain how to pick the right sub-code based on what the product actually is. We’ll also look at why rates still appear inconsistent online, where classification breaks down in real filings, and what tends to hold up when returns are reviewed so the numbers make sense beyond Excel.

What falls under HSN Code 2821?

HSN Code 2821 applies to a limited group of inorganic chemical products. It’s a narrow category. Most mistakes happen when people assume a product fits, use the code once, and don’t revisit it until something gets questioned later.

‍At its core, this code includes three categories:

‍Iron oxides: Ferric oxide (Fe₂O₃) is used in pigments. It’s also used in polishing powders and for adding color to cement and tiles.

‍Iron hydroxides: Materials used in chemical processing, water treatment, or as intermediates in pigment production.

‍Earth colours with ≥70% iron (as Fe₂O₃): Natural mineral pigments that meet the iron threshold. The 70% rule is non-negotiable. Fall short, and the code no longer applies.

That iron content test matters more than product appearance. A red or yellow pigment does not qualify on color alone. Lab composition decides the code.

Current GST rate for HSN 2821

Here’s the answer upfront.

All major sub-codes under HSN Code 2821 are subject to 18% GST today.

The rate does not change with usage.

The rate does not change by buyer type.

If the product fits the code, 18% applies.

GST Rates by HSN sub-code

HSN Code	Description	GST Rate
28211000	Iron oxides & hydroxides	18%
28211010	Iron oxides	18%
28211020	Iron hydroxides	18%
28212000	Earth colours (≥70% iron as Fe₂O₃)	18%

Rates like 5% or 12% still appear on older pages. Those reflect past notifications, not current GST treatment.

For invoicing, returns, and ITC, 18% is the rate in force.

Why do some sources show 5% or 12%

You still find pages listings 5% or 12% for iron oxides and hydroxides. That data comes from early GST rate schedules, not from what applies now.

‍Here’s what happened:

Initial GST notifications place some inorganic chemicals in lower slabs

Later revisions aligned iron oxides, hydroxides, and qualifying earth colours under 18%

Many lookup sites never remove old rate tables

Those older slabs remain searchable. They do not change present-day treatment.

18% is the applicable GST rate today for products classified under HSN 2821.

Lower percentages explain search confusion. They do not offer compliance relief.

Choosing the right sub-code under 2821

This is where most classification mistakes happen. Not at the rate level. At the sub-code level.

Use the product’s chemical nature, not how it’s marketed.

‍Here’s the simple split:

‍28211010: Iron oxides: Fe₂O₃-based materials are used in pigments, polishing compounds, tiles, and cement mixes.

‍28211020: Iron hydroxides: Used in chemical processing, treatment systems, or as intermediates.

‍28212000: Earth colours with ≥70% iron: Natural mineral pigments that meet the iron-content threshold.

Quick classification checklist

Before locking the code, check:

‍Composition

What does the chemical or lab report say?

End use

Pigment, additive, or chemical input?

Documentation

Supplier specs, MSDS, or lab analysis.

‍Pro tip:

Misclassification doesn’t reduce tax. It raises audit risk.

GST Implications for buyers and sellers

The rate is only the starting point. 18% GST affects how you bill, claim credit, and close returns.

For sellers

Charge 18% output GST on invoices under HSN 2821

Report the same HSN and rate in GSTR-1

Keep product classification consistent across invoices and filings

A mismatch here does not stay hidden for long.

For buyers

ITC remains available if the invoice shows the correct HSN and rate

Credit gets blocked or delayed if the classification slips

What breaks ITC

Wrong HSN sub-code

Wrong GST rate

Supplier reporting errors

How problems surface

GSTR-1 vs GSTR-3B mismatches flag the transaction

Buyers raise disputes to protect their credit

Audit notices follow repeated inconsistencies

Import and Export classification notes

HSN Code 2821 with HS Code 2821 for customs purposes. That alignment matters at the border.

Bills of entry and export invoices rely on HS classification

Incorrect coding delays clearance and triggers valuation queries

Supporting documents should match the declared code and product makeup

One thing to keep straight: customs classification does not change GST liability. A product cleared under HS 2821 still attracts 18% GST on domestic supply. Customs duty treatment and GST operate on separate tracks.

Common classification mistakes to avoid

A small classification slip creates outsized problems later. Most issues trace back to assumptions made too early.

‍Watch for these mistakes:

‍Treating earth colours as minerals: Visual appearance does not decide the code. Iron content does.

‍Ignoring the 70% iron threshold: Earth colours below the cutoff fall outside HSN 2821.

‍Copying supplier HSN blindly: Supplier codes help, but responsibility stays with the seller issuing the invoice.

‍Using old rate tables: Historical slabs still float online and confuse decisions.

‍Mixing sub-codes across invoices: When the details don’t match, it gets questioned during reconciliation.

Getting the classification right avoids that conversation.

Conclusion

At this point, you know the rate, the sub codes, and where things usually go wrong. That alone cuts down rework and avoids ITC issues later.

For HSN 2821, the GST rate is 18% across iron oxides, iron hydroxides, and qualifying earth colours. Old slabs explain search noise, not present-day treatment.

Sub-code accuracy matters. Composition, end use, and documentation decide classification, not color, naming, or supplier habits.

Consistency protects ITC. Matching HSN and rates across invoices and returns prevents disputes, mismatches, and audit follow-ups.

If classification and invoicing still feel manual, Swipe helps standardize HSN usage, validate rates, and keep GST aligned so the numbers you learned here stay correct in practice.

FAQs

Is GST always 18% for iron oxides?

Yes. Products classified under HSN Code 2821 are subject to 18% GST today. Older rates still appear online, though they reflect past schedules rather than current treatment.

Does usage change the GST rate?

No. Industrial use, resale, or processing does not affect the rate. Classification depends on composition, not application.

Can Earth colours fall under another chapter?

Yes. Earth colours with less than 70% iron as Fe₂O₃ fall outside HSN 2821 and may fit another casper based on material makeup.

What documents support HSN classification?

Use lab analysis reports, MSDS, and supplier specifications. These records support iron percentage and chemical identity during reviews.

Is supplier HSN enough for compliance?

No. Supplier help, though invoice responsibility stays with you. Always validate before filing returns.

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