Calculators
GST Calculator
Add or remove GST with an automatic CGST and SGST split.
Invoices and prices are calculated in your browser only. Nothing is logged or transmitted.
Base Amount & GST Rate
The applicable GST rate depends on the product or service classification and current GST rules. Verify the applicable HSN/SAC rate before invoicing or filing.
Tax Invoice Summary
For estimation and invoicing assistance only. Does not replace professional tax or legal advice. Verify current rate schedules with official tax authorities.
What this online GST calculator does
This online Goods and Services Tax (GST) calculator calculates both inclusive and exclusive GST amounts in seconds. Whether you need to add GST to a base invoice price or extract the net amount and tax portion from a gross total, it provides common GST rate options: 0%, 3%, 5%, 12%, 18%, and 28%, along with custom percentages.
It splits tax amounts into intra-state components (Central GST and State GST, 50/50 split) or inter-state integrated tax (IGST 100%) to assist with your invoice calculations.
The applicable GST rate depends on the product or service classification and current GST rules. Verify the applicable HSN/SAC rate before invoicing or filing. This calculator is a calculation utility designed for planning and does not determine legal tax compliance or replace professional tax advice.
How to calculate GST (Add or Remove GST)
Calculate tax breakdown and invoice amounts in three simple steps.
- Select calculation modeChoose "Add GST" (Exclusive) to add tax to a net base price, or "Remove GST" (Inclusive) to extract the tax from a gross amount.
- Enter your monetary amountEnter the net price or gross invoice total into the amount field.
- Pick your GST tax rateSelect common GST rate options (0%, 3%, 5%, 12%, 18%, 28%) or type a custom tax percentage.
- Select transaction typeChoose Intra-State to split into CGST + SGST (50% each) or Inter-State for 100% IGST.
- Review the invoice breakdownView net base amount, total tax amount, component tax breakdown, and the final invoice total.
Why use this GST calculator
Engineered for chartered accountants, small business owners, freelancers, and shoppers.
- Both Add GST & Remove GST modesSeamlessly toggle between forward markup calculations and reverse tax extraction from gross retail totals.
- Intra-state & inter-state tax splittingAutomatically calculates CGST and SGST splits for local sales or IGST for cross-border commercial transactions.
- Common GST rate presetsIncludes quick-select buttons for 0%, 3%, 5%, 12%, 18%, and 28% tax rates as well as custom percentages.
- Invoice-ready currency formattingFormats numbers clearly with standard separators and 2-decimal precision for direct entry into invoicing software.
- Complete financial privacyAll invoicing calculations run in your local browser runtime. Zero sales telemetry or ledger logs.
Your invoicing data remains strictly confidential
Business turnover, bill amounts, and transaction sizes are confidential commercial information that should never be leaked to third-party web apps.
ToolForForever computes all GST calculations directly in your browser. No HTTP requests are sent when you type amounts or change tax rates.
We do not store your invoice figures, customer bill amounts, or tax calculations.
Good to know
- To add GST (Exclusive): GST Amount = (Base Amount x Rate) / 100; Total = Base Amount + GST Amount.
- To remove GST (Inclusive): Base Amount = Total / (1 + Rate / 100); GST Amount = Total - Base Amount.
- Intra-state sales within the same state or union territory are split equally between CGST (Central) and SGST (State).
- Inter-state transactions between two different states or territories are subject to IGST (Integrated GST) in full.
Frequently asked questions
What is the formula to remove GST from a total price?
To remove GST from an inclusive total, use: Base Price = Total / (1 + Rate/100). The GST portion is then: GST Amount = Total - Base Price. For example, for $118 at 18% GST: Base = 118 / 1.18 = $100, and GST = $18.
What is the difference between CGST, SGST, and IGST?
CGST (Central GST) and SGST (State GST) apply to intra-state sales within the same state, split equally 50/50. IGST (Integrated GST) applies to inter-state sales across state borders and is collected as a single combined tax.
What items fall under different GST rate slabs?
Tax slabs vary according to specific HSN (goods) or SAC (services) codes. In general: 0% applies to essential unbranded foods; 3% covers gold and precious metals; 5% covers basic necessities; 12% covers selected processed foods; 18% covers standard IT and commercial services; and 28% covers luxury goods and automobiles. Always verify your item’s exact code with the latest official GST Council schedules.
How do I calculate GST on discounted products?
GST must always be calculated on the discounted sale price, not the original MRP sticker price. Deduct the discount first, then compute the GST on the net selling price.
Can this calculator be used for international VAT or Sales Tax?
Yes. By entering any country’s standard tax rate as a custom percentage, you can use the Add or Remove modes for any VAT, sales tax, or consumption tax worldwide.
Does this calculator store my business calculations?
No. All calculations are executed locally in your browser’s JavaScript memory and are never transmitted over the internet or saved.