GST Calculator for Inclusive, Exclusive and Invoice Prices
Calculate Indian GST on one item or a complete invoice. Add or extract GST, apply a pre-tax discount, compare CGST plus SGST with IGST, enter an additional cess, deduct eligible input tax credit and review every line of the calculation.
Last Updated: July 23, 2026. Rate presets reflect the GST structure in effect after September 22, 2025.
GST Invoice Calculator
Enter up to 10 items. Use one row for a quick add-GST or remove-GST calculation.
Your GST Result
| Item | Gross value | Discount | Taxable value | GST rate | GST | Cess | Line total |
|---|---|---|---|---|---|---|---|
| Total | ₹0 | ₹0 | ₹0 | Mixed | ₹0 | ₹0 | ₹0 |
How to Use This GST Calculator
- Select intra-state supply for a CGST and SGST or UTGST split. Select inter-state supply for IGST.
- Enter a description, quantity and price for the first item.
- Choose whether the entered unit price excludes GST or already includes GST.
- Enter a pre-tax discount. Select the notified GST rate or choose Custom rate.
- Enter an additional cess rate only when a current notification applies to the supply.
- Add more rows when one invoice contains items with different prices or rates.
- Enter eligible input tax credit only for a rough net-liability estimate.
- Select Calculate GST and review the taxable value, tax heads, line totals and warnings.
For a basic GST calculation, keep one row with quantity 1. Enter ₹10,000, choose price excludes GST and select 18%. The result shows taxable value ₹10,000, GST ₹1,800 and final price ₹11,800.
Current GST Rate Structure in 2026
India's GST rate structure changed from September 22, 2025. The system now primarily uses a 5% merit rate and an 18% standard rate, with a 40% special rate for specified luxury and sin supplies. Limited special rates such as 0.25% and 3% continue where notified. Exempt and zero-rated treatment also exists, but those classifications have different legal and input-credit consequences.
| Calculator option | Typical role | Intra-state display | Inter-state display |
|---|---|---|---|
| 0% | Arithmetic for a verified zero, nil or exempt rate | 0% CGST + 0% SGST | 0% IGST |
| 0.25% | Limited notified special rate | 0.125% + 0.125% | 0.25% IGST |
| 3% | Limited notified special rate | 1.5% + 1.5% | 3% IGST |
| 5% | Primary merit rate | 2.5% + 2.5% | 5% IGST |
| 18% | Primary standard rate | 9% + 9% | 18% IGST |
| 40% | Specified luxury or sin supplies | 20% + 20% | 40% IGST |
| Custom | Specific notification, legacy invoice or special case | Half + half | Full entered rate |
GST Calculation Formulas
Add GST to an exclusive price
Remove GST from an inclusive price
When the entered price already includes GST and no additional cess is embedded in that price, use the following method:
In this calculator, the price-inclusive option treats the selected GST as embedded in the entered price. A user-entered cess is then calculated separately on taxable value. If an invoice price includes both GST and cess, use the actual invoice breakup or professional software because a single inclusive-rate extraction may not match the notified valuation method.
Worked GST Examples
Example 1: Add 18% GST to ₹10,000
| Step | Calculation | Amount |
|---|---|---|
| Taxable value | Entered exclusive amount | ₹10,000 |
| Total GST | ₹10,000 × 18% | ₹1,800 |
| Intra-state split | CGST 9% + SGST 9% | ₹900 + ₹900 |
| Invoice total | ₹10,000 + ₹1,800 | ₹11,800 |
Example 2: Extract 18% GST from ₹11,800
Divide ₹11,800 by 1.18. The taxable value is ₹10,000 and the embedded GST is ₹1,800. Subtracting 18% of ₹11,800 would produce ₹2,124, which is incorrect because GST was charged on the lower taxable value.
Example 3: Apply a 10% discount before 18% GST
A ₹10,000 item with a 10% pre-tax discount has a gross value of ₹10,000 and discount of ₹1,000. Taxable value becomes ₹9,000. GST is ₹1,620 and the invoice total is ₹10,620. Post-supply discounts and credit-note treatment require separate statutory checks.
CGST, SGST, UTGST and IGST
Intra-state supply
When the supplier's location and the legally determined place of supply are in the same state, the combined GST is generally split equally between CGST and SGST. A Union Territory without a legislature generally uses CGST and UTGST.
Inter-state supply
When the supplier's location and place of supply are in different states or Union Territories, IGST generally applies. Imports and certain deemed inter-state supplies also use IGST treatment.
The customer's postal address alone does not settle every place-of-supply question. Goods involving movement, installation, bill-to and ship-to arrangements, immovable-property services, events, transport, online services and cross-border transactions have specific rules.
Input Tax Credit and Net GST Payable
GST normally permits eligible credit for tax paid on business inputs, input services and capital goods, subject to conditions and blocked-credit rules. The calculator subtracts the single eligible ITC amount you enter from total output GST plus entered cess. It does not allocate credit across IGST, CGST, SGST and cess ledgers.
Actual electronic-credit-ledger use follows statutory ordering and restrictions. SGST credit from one state cannot pay another state's SGST. Cess credit may have restricted use. Invoice possession, receipt of supply, supplier reporting, tax payment, return filing, time limits, reversals and blocked credits can affect eligibility. Use GST portal records and professional advice for filing.
Reverse Charge and Additional Cess
Reverse charge
Under reverse charge, the recipient rather than the supplier pays GST for specified supplies or situations. Selecting the reverse-charge box changes the payer note only. It does not decide whether reverse charge applies, generate a self-invoice or determine credit eligibility.
Additional cess
Some notified supplies can attract an additional levy. The calculator accepts a percentage and applies it to taxable value. Do not treat the 40% special GST rate and an additional cess as automatically cumulative. Check the current notification, valuation base and effective date. Tobacco-related levies changed again from February 2026, so older compensation-cess assumptions may be unsafe.
Zero-Rated, Nil-Rated and Exempt Supplies
A 0% arithmetic result does not make these legal categories identical.
- Zero-rated supply: Exports and supplies to SEZs can qualify, subject to the Integrated GST law and documentation. Input-credit and refund treatment can remain available.
- Nil-rated supply: The tariff rate is nil for the specified supply.
- Exempt supply: A notification or law exempts the supply. Related input tax credit can be unavailable or require reversal.
- Non-GST supply: The transaction falls outside GST levy. Other taxes or rules may apply.
Select 0% only after identifying the correct category. The calculator does not determine refund, LUT, bond, export documentation or ITC reversal.
Invoice Value, Discounts and Rounding
GST generally applies to the taxable value determined under Section 15 and related valuation rules. Freight, packing, commission and incidental expenses charged by the supplier can form part of value. This tool's “other invoice charge” uses the first item's GST and cess rates, so create a separate item row when a charge has a different treatment.
A discount recorded before or at supply and shown on the invoice generally reduces the taxable line value. Later discounts need agreement, invoice linkage and input-credit adjustment conditions. The calculator applies only a simple line-level percentage before tax.
When final rounding is selected, the tool rounds only the invoice grand total to the nearest rupee and reports the adjustment. Each line's internal calculation keeps decimal precision. Your accounting software, invoice policy or tax reporting may round at a different stage.
Common GST Calculation Mistakes
- Using outdated 12% or 28% presets after the September 2025 rate rationalisation.
- Subtracting the GST percentage directly from a tax-inclusive price.
- Selecting CGST plus SGST from the buyer's address without checking place of supply.
- Applying one GST rate to a mixed invoice containing separately priced supplies.
- Reducing taxable value for an unsupported post-supply discount.
- Claiming all purchase GST as ITC without checking blocked credits and documentation.
- Adding a cess merely because the supply uses the 40% special rate.
- Treating exempt and zero-rated supplies as identical.
- Ignoring reverse charge, composite supply, mixed supply or time-of-supply rules.
- Using calculator output as a tax invoice without verifying GSTIN, HSN/SAC and mandatory particulars.
Related Business and Tax Calculators
Use these tools for connected tax, import and business planning.
Frequently Asked Questions
How do I calculate GST on an exclusive price?
Multiply taxable value by the GST rate and divide by 100. Add GST and any separately applicable cess to taxable value to find the invoice total.
How do I remove GST from an inclusive price?
Divide the GST-inclusive amount by 1 plus the GST rate as a decimal. Subtract the resulting taxable value from the inclusive amount to find embedded GST.
What are the main GST rates in 2026?
After the September 22, 2025 changes, the structure primarily uses 5% and 18%, with 40% for specified luxury or sin supplies. Limited special rates such as 0.25% and 3% remain where notified.
Why are 12% and 28% not standard presets?
The September 2025 rationalisation removed the earlier 12% and 28% main slabs. Use Custom rate only for a legacy invoice or a specific current notification that requires another rate.
What is the difference between CGST, SGST and IGST?
CGST and SGST or UTGST generally apply together to an intra-state supply. IGST generally applies to an inter-state supply. The legal place of supply and supplier location control the result.
Does the calculator determine the correct HSN or SAC rate?
No. It calculates amounts from the rate you select. Verify HSN or SAC classification, description, conditions, exemptions and current notifications before invoicing.
Can I subtract input tax credit from output GST?
The calculator provides a rough net figure, but actual ITC must be eligible and used through the correct tax ledgers and statutory order. Blocked credits, reversals and documentation rules still apply.
Does 40% GST always include every cess?
No. Do not automatically add or remove a cess because a supply uses 40%. Check the current notification, levy, valuation base and effective date for that specific supply.
Can I use this result as a GST invoice?
Use the result to check arithmetic. A valid invoice also needs correct supplier and recipient details, GSTIN where required, serial number, date, HSN or SAC, place of supply, tax heads and other mandatory particulars.
Official References
Tax disclaimer: This calculator provides arithmetic estimates for education and invoice checking. It does not determine HSN or SAC classification, rate, exemption, place of supply, time of supply, reverse charge, input tax credit eligibility, tax-ledger use, return reporting or invoice validity. Verify current official notifications and obtain professional advice for material or disputed transactions.