How do I remove GST from an inclusive price?

Divide: net = gross × 100/(100+rate). ₹11,800 ÷ 1.18 = ₹10,000 net, ₹1,800 GST. Never multiply gross by the rate.

What is CGST vs SGST vs IGST?

Intra-state sales split GST equally as CGST (Centre) + SGST (State). Inter-state sales charge the full amount as IGST. Totals are identical.

What are the GST slabs?

0%, 0.25%, 1%, 1.5%, 3%, 5%, 7.5%, 12%, 18%, 28% (plus cess on some 28% goods). Most services: 12% or 18%; restaurants often 5%.

Is GST charged on discounted price?

Yes — on the transaction (discounted) value, not MRP. Discount first, then apply the slab to the net.

Do I need GST registration?

Generally above ₹20L (services) / ₹40L (goods) turnover, varying by state/category, plus inter-state and e-commerce sellers. Check current CBIC thresholds or ask a CA.

Financial · Free tool

GST Calculator

Add or strip GST — net, tax, gross plus CGST/SGST split.

₹10,000 plus 18% GST — is the invoice ₹11,800, and if a customer pays ₹11,800 inclusive, is the GST ₹1,800 or ₹1,627? (It is ₹1,627 — extracting is division, not multiplication.) Goods and Services Tax mistakes trigger the most common invoicing errors for freelancers and small businesses: wrong slab, wrong exclusive/inclusive direction, and forgotten CGST/SGST splits. This GST calculator handles both directions for all Indian slabs (0, 0.25, 1, 1.5, 3, 5, 7.5, 12, 18, 28%) plus any custom rate, with an automatic 50/50 CGST–SGST intra-state split.

GST is a destination-based value-added tax: businesses collect on sales, claim input credit on purchases, and remit the difference. Quoting exclusive (net + tax) is B2B standard; MRP/inclusive (tax-in) is retail standard. Mixing them misstates margins by the tax-on-tax illusion — a 18% 'removal' from ₹11,800 by multiplying ×0.82 gives ₹9,676 (wrong); dividing by 1.18 gives ₹10,000 (right). The tool shows net, GST, gross, and the CGST/SGST lines auditors expect on Indian invoices.

Choose Exclusive (add tax) or Inclusive (extract tax), enter amount and slab, and press Calculate. Export the three lines straight onto the invoice.

Updated 2026-09-01 · 7-min read · Formula + steps included

● GST workstation

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GST formulas

Exclusive: GST = net × r/100, gross = net + GST • Inclusive: net = gross × 100/(100+r), GST = gross − net

Adding tax multiplies by (1+r/100). Extracting divides by the same factor — never subtract r%. CGST = SGST = GST ÷ 2 for intra-state supply; IGST = full GST for inter-state. Slabs are policy-set; composition schemes differ — confirm with your CA for edge goods (gold 3%, mopeds, sin goods 28% + cess).

net: Pre-tax value (exclusive base). What the seller keeps before remittance.
r: GST slab % (e.g. 18). Must match HSN/SAC classification.
gross: Tax-inclusive price the buyer pays (MRP-style).

Worked example: ₹10,000 at 18%

Both directions, the numbers every freelancer should memorise:

Exclusive: GST = 10,000 × 0.18 = ₹1,800; gross = ₹11,800. CGST = SGST = ₹900.
Inclusive reversal: net = 11,800 × 100/118 = ₹10,000; GST = 11,800 − 10,000 = ₹1,800.
Wrong method exposed: 11,800 × 18% = ₹2,124 (overstates tax by ₹324). Division is mandatory.
Margin lens: seller keeps ₹10,000 either way; buyer pays ₹11,800 either way — direction only changes which figure you start from.

Result: Exclusive ₹10,000 → ₹1,800 GST → ₹11,800. Inclusive ₹11,800 → ₹10,000 net + ₹1,800 GST (₹900 + ₹900).

How to use this GST calculator

Direction first, slab second.

Step 1: Pick mode

Exclusive = 'add GST to my quote'. Inclusive = 'extract GST from what I was paid / MRP'.

Step 2: Enter amount

Net for exclusive, gross for inclusive. Check whether your input already hides tax.

Step 3: Pick slab

5/12/18/28% cover most goods/services; 0.25–3% for gems/gold; 0% for exempt. When unsure, check HSN/SAC or ask your CA.

Step 4: Invoice three lines

Copy net, CGST, SGST (or IGST inter-state) and gross. Keep GSTIN on the header for input credit.

Use cases

Daily GST decisions:

Freelancer quotes

Quote ₹50,000 + 18% = ₹59,000 to B2B clients who claim credit; quote ₹59,000 flat to consumers who cannot.

Retail MRP

₹999 MRP at 12% hides ₹107.14 tax (999−999×100/112). Margin plans must use ₹891.86 net, not ₹999.

Restaurant bills

5% without ITC (standalone) vs 18% with ITC (hotels) — slab changes the invoice the tool prices.

E-commerce

Marketplace payouts are often inclusive; extract net before deducting commission to find true margin.

Second-hand & composition

Margin schemes and 1–6% composition rates need CA sign-off — model standard slabs here, confirm edge cases offline.

Pro tips

Invoice like an accountant:

Memorise divisors: ÷1.05, ÷1.12, ÷1.18, ÷1.28 for instant inclusive extraction.
Show HSN/SAC + slab on every invoice — missing codes delay input credit for your buyer.
For inter-state sales label the full line IGST, not CGST+SGST; intra-state splits 50/50.
Claim ITC monthly: 18% on ₹2L of inputs is ₹36k of credit — unclaimed credit is pure margin lost.
Reconcile GSTR-2B before filing; mismatched supplier filings block your credit.

Common mistakes

Costly GST errors:

Extracting by multiplication

Gross × r% overstates tax (₹2,124 vs ₹1,800 above). Always divide by (100+r)/100.

Wrong slab

18% vs 12% on ₹10L is a ₹60k swing plus interest/penalty. Verify HSN, especially for works contracts and food.

Forgetting cess

28% sin/luxury goods often add compensation cess on top — model base GST here, add cess per notification.

No GSTIN, no credit

B2B buyers cannot claim without your valid GSTIN invoice. Unregistered sellers must say so upfront.

Disclaimer: General information only — not tax advice. Slabs, exemptions and thresholds change; confirm HSN/SAC classification and registration with a qualified CA or CBIC notifications.

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