FREE TOOL · UPDATED FOR GST 2.0 (SEPT 2025) · NO EMAIL REQUIRED
Calculate CGST, SGST, and IGST instantly. Supports the new GST 2.0 rate structure (0%, 5%, 18%, 40%) effective September 22, 2025. Toggle between intra-state and inter-state transactions. HSN code lookup helper included. No signup, no watermarks, no email gate.
Transaction Type
Intra-state (same state): CGST + SGST. Inter-state (different states): IGST.
Calculation Mode
Your amount is BEFORE tax — GST will be added on top.
Amount (₹)
Enter amount in INR. Indian numbering format (lakhs, crores) supported.
GST Rate (GST 2.0)
HSN Code (Optional)
Search by HSN code or product name — auto-fills the GST rate above.
Enter an amount to see the GST calculation.
REME automatically classifies CGST, SGST, and IGST on every receipt your employees submit via WhatsApp. No manual coding, no GST 2.0 rate confusion. Built for Indian finance teams handling 50–300+ employees.
The Goods and Services Tax (GST) is India's unified indirect tax system, replacing a patchwork of state and central levies that existed before 2017. Every business transaction in India falls into one of four GST scenarios — depending on whether the transaction is intra-state (within one state) or inter-state (across state lines), and what category of goods or services is being supplied.
For finance teams managing employee expenses, getting GST classification right matters for two reasons: input tax credit recovery (you can recover GST paid on legitimate business expenses) and audit compliance (incorrect GST classification triggers GST notices and audit findings).
When buyer and seller are in the same Indian state, GST is split equally between Central GST (CGST) and State GST (SGST). Example: an 18% GST on an intra-state transaction = 9% CGST + 9% SGST. The state retains the SGST portion; the central government collects CGST. From the buyer's perspective, the total tax remains 18% — but the breakdown matters for input tax credit reconciliation and GSTR filings.
When buyer and seller are in different states, the entire GST is collected as Integrated GST (IGST). Example: an 18% GST on an inter-state transaction = 18% IGST. The central government collects IGST and later distributes the state-portion to the destination state. For buyers, this simplifies bookkeeping (one tax line instead of two) but requires careful tracking for input tax credit claims.
For transactions within or to a Union Territory (e.g., Delhi, Chandigarh, Puducherry), the SGST equivalent is called UTGST (Union Territory GST). Functionally identical to SGST for most calculations. The calculator above treats UT transactions as intra-state and shows the CGST + SGST split — finance teams in UTs should mentally substitute UTGST for SGST in their books.
In September 2025, the GST Council restructured India's GST rate slabs as part of "GST 2.0." The changes affected millions of businesses overnight — particularly those using outdated calculators or accounting systems still hard-coded with the pre-2.0 rates. Here's what changed and what stayed the same:
Most everyday business expenses (office supplies, software, business meals, professional services, B2B transactions) now fall under the 18% slab. The simplification reduces classification disputes — but legacy invoices issued before September 22, 2025 still use old rates. Use the "Show legacy rates" toggle in the calculator above for historical calculations.
The most consequential GST mechanic for Indian finance teams is Input Tax Credit (ITC). When your company pays GST on legitimate business expenses, that GST is recoverable — meaning it flows back into your books as a credit against GST you collect on sales. For mid-market companies, proper ITC recovery typically returns 5–15% of GST paid as cash flow benefit annually.
But ITC recovery requires documentation that most manual expense management approaches don't capture systematically:
ITC requires a proper tax invoice from a GST-registered supplier — including the supplier's GSTIN, your company's GSTIN, line-item breakdown, and HSN/SAC codes. Cash receipts without GSTIN don't qualify. A common audit finding: ~20–30% of submitted business expenses lack ITC-eligible documentation.
ITC is only claimable once goods are physically received or services rendered. For prepaid services or advance payments, ITC must be deferred until actual delivery. Tracking this manually across hundreds of transactions per month is the source of most ITC reconciliation errors.
ITC claims must match what the supplier reports in their GSTR-1 filing — visible in your GSTR-2A/2B. If the supplier doesn't file or files late, your ITC claim gets blocked. This is one of the biggest pain points for Indian finance teams: chasing suppliers to file on time.
ITC must be claimed within 180 days of the invoice date. After that, the claim is lost. Manual expense management workflows where receipts sit in employee inboxes for weeks before submission are the leading cause of expired ITC claims.
REME automates ITC documentation: every receipt submitted via WhatsApp gets validated for GSTIN, classified by GST slab and CGST/SGST/IGST split, and exported in formats compatible with your GSTR filings. Manual reconciliation goes from days to hours.
See how REME handles GST automationNot every Indian business is required to register for GST. The thresholds are turnover-based and vary by state and business type. As of 2026, the general thresholds are:
Special category states: Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura, and Uttarakhand. Verify current thresholds at gst.gov.in before registration decisions.
GST CALCULATOR FAQ
GST is calculated as a percentage of the transaction value. For a ₹1,00,000 transaction at 18% GST: GST amount = ₹18,000, total amount = ₹1,18,000. For intra-state transactions (buyer + seller in same state), the GST splits 50/50 between CGST and SGST — so 18% becomes 9% CGST + 9% SGST. For inter-state transactions, the entire GST is collected as IGST. The calculator above handles both scenarios automatically with the transaction type toggle.
CGST (Central GST) is collected by the central government, SGST (State GST) by the state where the buyer is located. They apply to intra-state transactions and split the total GST equally. IGST (Integrated GST) applies to inter-state transactions where buyer and seller are in different states — the central government collects it and distributes the state portion to the destination state. The total amount is the same either way (e.g., 18% total). The breakdown matters for filing GSTR returns and reconciling input tax credit.
The current GST rate structure in India (effective September 22, 2025) has four main slabs: 0% (exempt — essentials, education, healthcare), 5% (common goods, transport), 18% (most goods and services — the default for business expenses), and 40% (luxury and sin goods — tobacco, luxury cars). The previous 12% and 28% slabs were deprecated; goods in those tiers were redistributed to 18% or 40%. Use the calculator's "Show legacy rates" toggle for historical calculations on transactions before September 22, 2025.
ITC is the GST you've paid on business expenses that you can recover by setting it off against GST you collect on sales. For example, if you paid ₹18,000 GST on business expenses this month and collected ₹50,000 GST from customers, your net GST liability is ₹50,000 - ₹18,000 = ₹32,000. The calculator above shows the GST amount per transaction; aggregating these across your monthly business expenses gives your ITC pool. Critical caveat: ITC must be claimed within 180 days of invoice date.
Under the reverse charge mechanism, the buyer (recipient of goods or services) pays GST directly to the government instead of the supplier. RCM applies to specific transactions: goods/services from unregistered suppliers above thresholds, certain notified categories (legal services, transport of goods by GTA, services from foreign suppliers), and goods notified by the GST Council. Under RCM, the buyer can typically claim ITC on the GST paid — it's a neutral cash-flow exercise but creates additional compliance reporting requirements.
Intra-state transactions (buyer and seller in the same state) attract CGST + SGST split equally. Example: ₹1,00,000 at 18% intra-state = ₹9,000 CGST + ₹9,000 SGST = ₹18,000 total GST. Inter-state transactions (different states) attract IGST as a single line. Example: ₹1,00,000 at 18% inter-state = ₹18,000 IGST. The total GST burden is identical (18%) — the difference is in the tax authority allocation and how it appears in your GSTR returns.
GST registration is mandatory for businesses exceeding turnover thresholds: ₹40 lakhs annually for goods (₹20 lakhs in special category states), ₹20 lakhs annually for services (₹10 lakhs in special category states). Below these thresholds, registration is voluntary. However, certain categories require GST registration regardless of turnover: inter-state suppliers, e-commerce operators, casual taxable persons, agents, and input service distributors. Voluntary registration can be strategic for B2B businesses whose customers want to claim ITC on transactions.
GST exclusive (Add GST mode in the calculator): you have the pre-tax amount and want to add GST on top. Formula: total = base × (1 + GST rate). Example: ₹1,00,000 + 18% GST = ₹1,00,000 × 1.18 = ₹1,18,000. GST inclusive (Remove GST mode): you have the post-tax amount and want to extract the GST and base. Formula: base = inclusive amount ÷ (1 + GST rate). Example: ₹1,18,000 ÷ 1.18 = ₹1,00,000 base + ₹18,000 GST. The calculator above handles both with the calculation mode toggle.
HSN (Harmonized System of Nomenclature) is an internationally standardized product classification code. India uses 4-digit, 6-digit, or 8-digit HSN codes to classify goods (and SAC — Service Accounting Codes — for services). The HSN code determines which GST slab applies (0%, 5%, 18%, or 40%). For businesses with annual turnover above ₹5 crore, including HSN codes on tax invoices is mandatory. The HSN lookup in the calculator above helps identify your product's GST rate by searching either the code or product name.
Other free tools from REME plus relevant guides.
Drag-and-drop a receipt — REME's AI extracts vendor, amount, GST breakdown, and line items in real time.
Try the scanner → TOOL · LIVEFree interactive template. Multi-currency, real-time totals, export to Excel/CSV/PDF.
Open template → TOOL · COMING SOONAustralian GST 10% with business-expense input tax credit mode. Coming May 2026.
Notify me when ready → PRODUCTREME's policy engine classifies CGST/SGST/IGST on every employee receipt — no manual coding, audit-ready reporting.
See the workflow → SOLUTIONSBuilt specifically for finance teams in Indian companies handling 50–300+ employees. GST-native, GSTR-compatible, audit-ready.
Read more → PRICINGSame flat per-user pricing for every customer. Published, transparent, no carve-outs. From $8/user/month.
See pricing →GST 2.0 made compliance simpler. Manual classification didn't.
REME's policy engine identifies CGST, SGST, and IGST on every employee receipt submitted via WhatsApp. GSTIN validation, HSN classification, and ITC documentation — handled automatically. Built specifically for Indian finance teams. Backed by our 80% adoption guarantee.
The Adoption Guarantee
If your team doesn't hit 80%+ adoption within 30 days of rollout, we waive the next 60 days of paid usage. WhatsApp-based submission delivers 90%+ adoption in week one — we put our pricing where our promise is.
