What is a GST calculator?
A GST calculator helps you estimate tax amounts from prices and rates you provide. It is a maths tool — not a substitute for classifying supplies or filing returns.
Free tools
Free GST Calculator for India
Add or remove GST, calculate taxable value, and split tax into CGST, SGST or IGST. Private, browser-based maths — not tax advice.
Checks
- CGST + SGST selected. Confirm this supply is treated as intrastate under applicable place-of-supply rules.
Display currency does not convert exchange rates. Indian GST calculations are normally denominated per applicable Indian requirements.
Inputs
Preset rates are provided for calculation convenience. Verify the applicable rate for your goods or services using current official guidance.
Actual tax treatment of discounts can depend on transaction terms and documentation. Verify treatment where necessary.
Result summary
Original / gross
₹1,000.00
Discount
₹0.00
Taxable value
₹1,000.00
GST rate
18.00%
Total GST
₹180.00
CGST
₹90.00
SGST
₹90.00
IGST
₹0.00
Cess
₹0.00
Final amount
₹1,180.00
Effective tax rate
18.00%
Breakdown & working
Before GST: ₹1,000.00 · GST amount: ₹180.00 · After GST: ₹1,180.00
Formula: GST = taxable × 18 ÷ 100; Final = taxable + GST (+ cess/charges)
- Base / unit amount: ₹1,000.00
- Quantity: 1
- Gross: ₹1,000.00
- Discount: ₹0.00
- Taxable value: ₹1,000.00
- GST rate: 18%
- Total GST: ₹180.00
- CGST: ₹90.00
- SGST: ₹90.00
- Final amount: ₹1,180.00
Rate comparison (informational)
Does not imply which rate is legally applicable.
| Rate | GST | Inclusive | CGST | SGST | IGST |
|---|---|---|---|---|---|
| 0.00% | ₹0.00 | ₹1,000.00 | ₹0.00 | ₹0.00 | ₹0.00 |
| 5.00% | ₹50.00 | ₹1,050.00 | ₹25.00 | ₹25.00 | ₹0.00 |
| 12.00% | ₹120.00 | ₹1,120.00 | ₹60.00 | ₹60.00 | ₹0.00 |
| 18.00% | ₹180.00 | ₹1,180.00 | ₹90.00 | ₹90.00 | ₹0.00 |
| 28.00% | ₹280.00 | ₹1,280.00 | ₹140.00 | ₹140.00 | ₹0.00 |
| 18.00% | ₹180.00 | ₹1,180.00 | ₹90.00 | ₹90.00 | ₹0.00 |
How GST is calculated here
Add GST: GST = taxable × rate ÷ 100. Final = taxable + GST (+ optional cess and charges).
Remove GST: Base = inclusive × 100 ÷ (100 + rate). GST = inclusive − base.
CGST / SGST: Each is half of total GST when you select intrastate treatment.
IGST: Full GST amount when you select interstate treatment.
Rounding: Intermediate math uses decimal.js precision; displayed money amounts use half-up rounding to your selected decimal places (default 2).
This tool does not classify goods, determine place of supply, or replace official GST guidance.
Saved calculations
Up to 30 calculations in this browser only.
No saved calculations yet. Use “Save calculation in this browser”.
GST calculation guide
How to calculate GST
Decide whether your price is exclusive or inclusive of GST, apply any discount to arrive at taxable value, then apply the rate. Split into CGST/SGST or IGST only after you know the correct treatment.
How to add GST to a price
Multiply the taxable amount by the rate and divide by 100. Add that GST to the taxable amount for the customer-facing total.
How to remove GST from an inclusive price
Divide the inclusive amount by (1 + rate/100), or multiply by 100/(100+rate). The difference is the GST embedded in the price.
GST-inclusive vs GST-exclusive pricing
Exclusive pricing shows base + tax separately. Inclusive pricing quotes a single shelf price that already includes tax. Use the matching calculator mode so you do not double-tax.
What are CGST and SGST?
For many intrastate supplies, GST is shared between Centre and State as CGST and SGST. This calculator splits total GST in half when you select that treatment.
What is IGST?
IGST typically applies to interstate supplies. When selected here, the full GST amount is labelled IGST.
Intrastate vs interstate GST calculation
The legal distinction depends on place-of-supply and related rules. Version 1 requires you to choose the split; it does not auto-detect from addresses.
How discounts affect GST calculation
In this model, eligible discounts reduce taxable value before GST. Real-world treatment can depend on how discounts are documented.
How to calculate GST on multiple products
Compute each line with its own rate and inclusive/exclusive setting, then sum taxable values, GST components, cess, and charges for a grand total.
How GST rounding works
Web6 uses decimal arithmetic and half-up rounding for displayed money. Your books may follow a specific invoicing round-off policy — align with your accountant where needed.
How to verify the applicable GST rate
Confirm the rate for your goods or services using current CBIC notifications, GST Council decisions, and professional advice. Preset buttons here are not a legal rate schedule.
What is a taxable value?
Taxable value is the value on which GST is charged after considering the price, discounts, and charges you include in the model.
GST calculator examples
₹1,000 exclusive at 18% → GST ₹180, total ₹1,180. ₹1,180 inclusive at 18% → base ₹1,000, GST ₹180. Intrastate ₹180 GST → CGST ₹90 + SGST ₹90.
Common GST-calculation mistakes
Using the wrong inclusive/exclusive mode, applying GST before discounts incorrectly, assuming a preset rate is always legal, and auto-assuming CGST/SGST without checking place of supply.
GST calculator vs GST invoice generator
This calculator focuses on tax maths. The Invoice Generator helps create invoice layouts with GST fields. Neither replaces e-invoicing or GST Portal filing.
FAQ
GST calculator FAQs
Straight answers about add/remove GST, CGST/SGST/IGST, privacy, and what this tool does not do.
What is a GST calculator?
A GST calculator estimates Goods and Services Tax on amounts you enter — adding GST, removing GST from inclusive prices, and optionally splitting CGST/SGST or IGST. The Web6 tool runs entirely in your browser.
How is GST calculated?
For exclusive amounts: GST = taxable value × rate ÷ 100, and final = taxable + GST. For inclusive amounts: base = inclusive × 100 ÷ (100 + rate), and GST = inclusive − base.
How do I add 18% GST?
Choose Add GST, enter the base amount, select 18% (or custom), and read the GST amount and final total. Example: ₹1,000 + 18% = ₹180 GST and ₹1,180 total.
How do I remove GST from an inclusive amount?
Use Remove GST mode, enter the inclusive total and rate. The calculator returns the base price and GST included.
What is the formula for reverse GST?
Base amount = inclusive amount × 100 ÷ (100 + GST rate). GST amount = inclusive amount − base amount.
What is taxable value?
In this tool, taxable value is the amount on which GST is computed after discounts and eligible before-GST charges, based on the values you enter.
What is CGST?
Central GST. When you select intrastate treatment, this calculator shows CGST as half of total GST for estimation.
What is SGST?
State GST. Under intrastate treatment in this calculator, SGST is the other half of total GST.
What is IGST?
Integrated GST. When you select interstate treatment, the full GST amount is shown as IGST.
When should CGST and SGST be used?
Typically for verified intrastate supplies under place-of-supply rules. This tool does not decide place of supply — you must select the treatment.
When should IGST be used?
Typically for verified interstate supplies. Confirm with applicable rules or a professional; the calculator only splits amounts based on your selection.
Does the calculator determine place of supply?
No. Version 1 does not infer legal tax treatment from states or postal codes. You choose CGST+SGST, IGST, or total only.
Can I enter a custom GST rate?
Yes. Presets are for convenience. You may enter any custom percentage within configured limits and should verify the legal rate separately.
Can I calculate GST on multiple products?
Yes. Multiple Items mode supports per-line quantity, price, discount, rate, inclusive/exclusive pricing, optional HSN/SAC reference, and cess.
Can different items have different GST rates?
Yes. Each line can use its own rate and tax treatment.
Can I calculate GST after a discount?
Yes. Percentage or fixed discounts reduce taxable value in the model. Actual legal treatment of discounts can depend on documentation.
Can I add shipping charges?
Yes in Multiple Items mode. Charges can be before GST, after GST, with a separate rate, or with no GST in this calculation.
Can I calculate cess?
Yes as an optional percentage, fixed, or per-unit amount. Cess is off by default and is not assumed for all goods.
Does the tool store my data?
Calculations stay in your browser. Drafts use sessionStorage. Saves use localStorage only when you choose Save. Nothing is sent to Web6 servers for storage.
Can I save calculations?
Yes. Explicitly save up to 30 calculations locally, then open, rename, duplicate, export, or delete them.
Can I export a PDF?
Yes. PDFs are generated in the browser with inputs, breakdown, a rate comparison table, and a disclaimer.
Can I use it on mobile?
Yes. The layout is mobile-friendly with accessible tabs and touch targets.
Is this an official government calculator?
No. Web6 is not affiliated with the GST Portal, GST Council, or CBIC. Use official sources to verify rates and rules.
Does it verify GST rates?
No. It does not look up HSN/SAC rates or classify supplies. Verify rates via official CBIC/GST guidance.
Does it provide tax advice?
No. It provides mathematical estimates only — not tax, accounting, or legal advice.
Can I use it for Shopify pricing?
Yes as a pricing helper for exclusive/inclusive GST maths. It does not connect to Shopify Admin.
Can I use it for invoices?
You can export breakdowns for reference. For invoice layouts, use the Web6 Invoice Generator. This calculator does not create e-invoices or IRNs.
What is the difference between GST-inclusive and GST-exclusive?
Exclusive prices exclude GST (tax is added). Inclusive prices already contain GST (tax is stripped with the reverse formula).
How are decimal values rounded?
Calculations use decimal.js. Displayed amounts use half-up rounding to your selected decimal places (default two).
Where can I verify current GST rates?
Use official CBIC GST rate information, GST Council communications, and the GST Portal, or consult a qualified professional.
Official references
Verify current rates and rules from official sources. Web6 is not a government portal.
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- Tools directory
More free browser tools from Web6.
- Contact Web6
Talk through ecommerce and software delivery.
Related pages are separate products. This calculator does not claim official GST integration.