Free Tool · CGST Act 2017 · IGST Act 2017
GST Calculator CGST / SGST / IGST
Add GST to a base amount or extract GST from a GST-inclusive price. Splits into CGST + SGST for intra-state transactions and IGST for inter-state transactions. Covers all notified GST rate slabs. All calculations are 100% client-side.
Reviewed by Harun Raaj, CA — ICAI Membership No. 238303 · Firm Reg. 19027S · Updated July 2026
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Statutory Basis
Every computation in this tool is based on the following specific statutory provisions.
CGST — Intra-state Supplies
Section 9 of the Central Goods and Services Tax Act, 2017 — levy of central tax on intra-state supply of goods or services. Tax is split equally between CGST and SGST/UTGST at half the applicable rate each.
SGST / UTGST — Intra-state Supplies
Section 9 of the respective State GST Act / Section 7 of the Union Territory GST Act, 2017 — state/UT component of intra-state GST, collected at half the applicable rate.
IGST — Inter-state Supplies
Section 5 of the Integrated Goods and Services Tax Act, 2017 — levy of integrated tax on inter-state supply of goods or services at the full applicable rate.
GST Rate Slabs
Rates notified by the GST Council under the CGST (Rate) Notification and IGST (Rate) Notification — 0%, 0.1%, 0.25%, 1.5%, 3%, 5%, 6%, 7.5%, 12%, 18%, 28%.
Input Tax Credit (ITC)
Section 16 of the CGST Act, 2017 — every registered person is entitled to take credit of input tax on supply of goods or services used in the course of business, subject to conditions and restrictions.
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Frequently Asked Questions
What are the GST rate slabs in India?+
GST in India has four main rate slabs: 5%, 12%, 18%, and 28%, plus a zero rate for exempt goods and services. Luxury and sin goods attract a cess over 28%. Source: CGST Act, 2017 read with GST Rate Schedules.
How is GST calculated on a price inclusive of GST?+
For a GST-inclusive price, the GST amount = Price × Rate ÷ (100 + Rate). Example: For ₹1,180 inclusive of 18% GST: GST = 1,180 × 18/118 = ₹180. Base price = ₹1,000. Source: Section 15, CGST Act, 2017.
What is the threshold for GST registration?+
Aggregate turnover exceeding ₹40 lakh (goods) or ₹20 lakh (services) in a financial year requires mandatory GST registration. For special category states, thresholds are ₹20 lakh (goods) and ₹10 lakh (services). Source: Section 22, CGST Act, 2017.
Is GST charged on exports?+
Exports of goods and services are zero-rated under Section 16 of the IGST Act — meaning 0% GST is charged, but the exporter can claim refund of input tax credit (ITC) on inputs used in exports. Source: Section 16, IGST Act, 2017.
What is the difference between CGST, SGST, and IGST?+
For intra-state supplies: CGST (Central) + SGST (State) each at half the total rate. For inter-state supplies: IGST (Integrated) at the full rate, collected by Centre and shared with destination state. Source: Articles 246A, 269A, Constitution of India; CGST/IGST Acts, 2017.
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