💰 GST Calculator
India's current GST slabs (post September 2025 rate reform): 0%, 5%, 18%, and 40% for select luxury/sin goods. 12% and 28% are shown here for a few transitional categories (e.g. bricks, older contracts) that still use them — check the current rate for your specific item below.
GST on construction materials & works contracts
Rates below reflect the GST Council's rate rationalisation effective 22 September 2025. Always confirm the HSN/SAC code and current rate for your exact item before billing — rates can change.
| Item | HSN/SAC | GST Rate |
|---|---|---|
| Cement (OPC, PPC) | 2523 | 18% |
| TMT steel bars / rods (all grades) | 7213 / 7214 | 18% |
| Sand & aggregate | 2505 / 2517 | 5% |
| Bricks (fired clay / fly ash) | 6901 | 12% with ITC, or 6% without ITC |
| Ceramic / vitrified tiles | 6907/6908 | 18% |
| Ready-mix concrete | 3824 | 18% |
| General works contract (construction service) | 9954 | 18% |
| Govt. infrastructure works contract (roads, bridges, metro) | 9954 | 12% with full ITC |
| Affordable housing construction | 9954 | 1% (no ITC) |
CGST, SGST & IGST — what's the difference
GST in India splits differently depending on where the buyer and seller are located. For a sale within the same state, the GST rate is split equally into CGST (Central GST, goes to the centre) and SGST (State GST, goes to the state) — each is exactly half the total rate. For a sale between two different states, the full rate is charged as a single IGST (Integrated GST), collected by the centre and apportioned to the destination state. The total tax paid is the same either way — only the split changes.
How the calculation works
Adding GST
GST amount = base amount × (rate ÷ 100). Total = base amount + GST amount.
Removing GST
Base amount = total ÷ (1 + rate ÷ 100). GST amount = total − base amount.
Splitting the tax
Intra-state: CGST = SGST = GST amount ÷ 2. Inter-state: IGST = full GST amount.
From calculation to a real RA bill
A one-off GST check is useful, but a Running Account (RA) bill needs GST applied automatically on every billed quantity, with retention deducted correctly and the split (CGST+SGST or IGST) set once per client — not recalculated by hand every time. True Site Sync applies your project's GST and retention terms automatically to every RA bill raised from site measurements.
Frequently asked questions
How do you calculate GST on an amount?
To add: GST = base × (rate÷100), total = base + GST. To remove: base = total ÷ (1 + rate÷100), GST = total − base.
What is the difference between CGST, SGST and IGST?
Intra-state sales split the rate equally into CGST + SGST. Inter-state sales charge the full rate as IGST. Total tax is the same either way.
What is the current GST rate on cement?
18% (HSN 2523), reduced from 28% after the September 2025 rate reform.
What is the GST rate on steel/TMT bars?
18% across all diameters and grades (HSN 7213/7214).
What GST rate applies to a construction works contract?
18% generally; 12% with full ITC for government infrastructure works; 1% for affordable housing.
What are the current GST slabs in India?
Since September 2025: 0%, 5%, 18%, and 40% for select luxury/sin goods, with a few transitional categories still at 12%/28%.
GST, applied automatically on every bill
True Site Sync handles GST and retention on every RA bill — no manual calculation. Start free.
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