About this calculator
GST Calculator — explained
The GST Calculator helps you compute Goods and Services Tax on any amount at any GST rate (5%, 12%, 18%, 28%) — whether you have the GST-inclusive total or the base (exclusive) amount. The calculator also splits the GST into CGST and SGST automatically for intra-state invoices, and instantly shows the net price, tax amount, and total. Ideal for small business owners, freelancers, traders, accountants, chartered accountants, GST consultants, and consumers reconciling everyday invoices.
GST replaced India's earlier patchwork of central and state taxes (VAT, service tax, excise) when it rolled out in 2017, and now applies to almost every B2B and B2C transaction in India. This free online GST calculator is mobile-friendly and works for both exclusive and inclusive scenarios with one click. Backed by AMFI Registered MFD Nithin Finserv.
What is the GST Calculator?
Goods and Services Tax (GST) is India's unified indirect tax on the supply of goods and services. It replaced multiple central and state taxes in 2017 and is governed by the GST Council. GST has a multi-slab structure — 0%, 5%, 12%, 18%, 28% — plus cess on luxury and sin goods. Intra-state transactions split GST into CGST (Central) + SGST (State); inter-state transactions are taxed as IGST (Integrated). Exports are zero-rated, imports are charged IGST.
How it works — the formula
Exclusive (you have the base amount): GST = amount × rate / 100; Total = amount + GST. Inclusive (you have the total): Base = amount × 100 / (100 + rate); GST = amount − base. For intra-state supplies, CGST = SGST = GST / 2. For inter-state or imports, the full GST is IGST instead.
How to use this calculator
- 1Enter the amount in rupees
- 2Pick the GST rate — 5%, 12%, 18%, or 28%
- 3Choose whether the amount is exclusive or inclusive of GST
- 4Read the base price, GST amount, CGST, SGST, and total
- 5Use the output directly in invoices, books of accounts, or tax filings
Key features
- ✓Handles both inclusive and exclusive GST calculations
- ✓Auto-splits into CGST and SGST
- ✓All four standard GST slabs supported (5/12/18/28)
- ✓Instant calculation with no rounding errors
- ✓Free, mobile-friendly, no signup
Frequently asked questions
What are the GST rates in India?
India has a multi-slab GST structure with rates of 0%, 5%, 12%, 18%, and 28%. Most goods and services fall in the 5–18% range. Luxury and sin goods are at 28% plus cess. Essentials like fresh food are at 0%.
What is the difference between CGST, SGST, and IGST?
CGST is collected by the Centre, SGST by the State — both apply on intra-state (same-state) supplies, each at half the total GST rate. IGST is collected by the Centre on inter-state supplies and imports, at the full GST rate. All three reach the same total tax on the buyer.
How do I calculate reverse GST (exclude GST from a total)?
Use this calculator's 'Inclusive of GST' option. The formula is base = amount × 100 / (100 + rate). For a ₹118 inclusive amount at 18% GST, the base is ₹100 and GST is ₹18.
Is GST applicable on mutual fund investments?
GST is applicable on the management fees and TER (Total Expense Ratio) charged by mutual fund houses, not on the principal or returns. The fund's TER already accounts for GST, so you don't pay GST separately on your investment amount.
What is the GST threshold for small businesses?
GST registration is mandatory if your annual turnover exceeds ₹40 lakhs for goods (₹20L for services). Special category states have lower thresholds (₹20L for goods, ₹10L for services). Voluntary registration is allowed below these thresholds.
What is the GST composition scheme?
A simplified scheme for small businesses with turnover up to ₹1.5 crores (₹75L for services), where you pay GST at concessional rates (1–6%) without claiming input tax credit. Reduces compliance burden but limits B2B sales.
Can I claim GST refund?
Yes — in specific cases like exports (zero-rated), inverted duty structure, excess input tax credit, or tax paid in error. Refund applications must be filed within 2 years from the relevant date.
What is e-invoicing under GST?
Mandatory electronic invoicing for businesses with turnover above ₹5 crores (as of 2024). Invoices must be reported on the IRP portal before issue and carry an Invoice Reference Number (IRN). Smaller businesses may opt in voluntarily.