How do I calculate a GST-exclusive invoice total?

Multiply the taxable base value by the GST rate, divide by 100, and add the result to the base. For ₹10,000 at 18%, GST is ₹1,800 and the invoice total is ₹11,800.

How do I remove GST from an inclusive amount?

Divide the GST-inclusive total by one plus the rate as a decimal. At 18%, divide by 1.18. A ₹11,800 inclusive total therefore contains a ₹10,000 base and ₹1,800 GST.

When are CGST and SGST used instead of IGST?

A taxable intra-state supply generally splits the applicable GST equally into CGST and SGST. A taxable inter-state supply generally uses IGST. Place-of-supply and registration rules can be nuanced, so confirm unusual cases with a qualified tax adviser.

Does receiving an invoice through UPI change the GST rate?

No. UPI is a payment method. GST treatment follows the underlying goods or services, supplier and recipient locations, registration status, exemptions, and current classification—not whether the customer paid by UPI.

Which SAC code should an Indian SaaS business use?

There is no universal SaaS code independent of the actual supply. CBIC classifications include 998313 for IT consulting and support, 998314 for IT design and development, and 998315 for hosting and infrastructure provisioning. Match the contract and invoice description with professional advice.

5% · 12% · 18% · 28% · private calculation

GST invoice value calculator

Add GST to a taxable value or extract it from an inclusive total, then split the tax into CGST and SGST or calculate IGST.

Initial Amount

GST Rate

Supply Type

Intra-State

Same state (CGST+SGST)

Inter-State

Other state (IGST)

Advanced: Add Profit Margin

Profit % (Calculates Selling Price from Cost Price)

If filled, 'Initial Amount' is treated as Cost Price.

Standard Rate Presets

Choose the rate shown in the current official classification for your supply; product names alone do not determine GST treatment.

Calculation Summary

Base Amount₹0.00

Total GST 18%+₹0.00

CGST (9%)₹0.00

SGST (9%)₹0.00

Final Total

₹0.00

India's Smartest Online GST Calculator

Calculating GST shouldn't be a hassle. Whether you are generating an invoice, checking a bill, or calculating profit margins, our free online GST calculator gives you instant, accurate results with full CGST, SGST, and IGST breakdowns.

How to calculate GST?

The formula for calculating GST is simple, but depends on whether the amount is exclusive or inclusive of GST.

1. Add GST (Exclusive)

Use this when you have the base price and need to add GST to get the final selling price.

GST Amount = (Base Price × Rate) / 100
Total = Base Price + GST Amount

2. Remove GST (Inclusive)

Use this when you have the final MRP and want to find the original base price and the tax component.

Base Price = Total / (1 + (Rate/100))
GST Amount = Total - Base Price

Understanding CGST, SGST, and IGST

India's GST system is a dual-tax model. Depending on where the buyer and seller are located, different taxes apply:

Intra-State (Same State): When the buyer and seller are in the same state. The GST is split equally into CGST (Central GST) and SGST (State GST). Example: 18% GST becomes 9% CGST + 9% SGST.
Inter-State (Different States): When the buyer and seller are in different states. The entire tax is collected as IGST (Integrated GST).

Current GST Slab Rates in India (2026)

GST Rate	Common Items / Services
0% (Nil)	Fresh fruits/vegetables, milk, eggs, bread, salt, printed books.
5%	Packaged food items, footwear (below ₹1000), apparel (below ₹1000), transport services.
12%	Computers, processed food, apparel (above ₹1000), business class air tickets.
18%	IT services, SaaS, telecom, financial services, branded garments, most electronics. (Standard Rate)
28%	Automobiles, luxury items, aerated drinks, tobacco, cement.

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Exclusive value

Add GST to the taxable base

When the quoted amount excludes tax, calculate GST directly on the taxable base. For an 18% service invoice:

base value = ₹10,000
GST        = ₹10,000 × 18 / 100 = ₹1,800
total      = ₹10,000 + ₹1,800   = ₹11,800

For an intra-state supply at 18%, the ₹1,800 tax is normally shown as ₹900 CGST and ₹900 SGST. For an inter-state supply, it is normally ₹1,800 IGST, subject to applicable place-of-supply rules.

Inclusive value

Extract GST from the final total

Do not calculate 18% of the inclusive total. Divide by 1.18 to recover the base:

inclusive total = ₹11,800
base value      = ₹11,800 / 1.18 = ₹10,000
GST included    = ₹11,800 - ₹10,000 = ₹1,800

The calculator keeps two decimal places for the display. Your invoicing system should apply one documented rounding policy consistently at line or invoice level.

Classification references

SaaS and payment-service SAC codes

These are official service-classification descriptions, not automatic tax advice. The correct code depends on what your contract actually supplies. Confirm the current rate, notification, exemption, export treatment, and place of supply with a chartered accountant.

SAC	Official classification description	How to use the reference
998313	Information technology consulting and support services	Potential reference where the contracted supply is IT consulting or support.
998314	Information technology design and development services	Potential reference for qualifying software design and development work.
998315	Hosting and information technology infrastructure provisioning	Potential reference when the actual supply is hosting or infrastructure provisioning.
997158	Financial transactions processing and clearing-house services	Classification reference for qualifying transaction-processing or clearing services.
997159	Other services auxiliary to financial services	A residual auxiliary-financial-services reference; not a default code for every payment product.

CBIC service classification annexure → GST Council service rate schedule →

Questions

GST invoice calculator FAQ

How do I calculate a GST-exclusive invoice total?: Multiply the taxable base value by the GST rate, divide by 100, and add the result to the base. For ₹10,000 at 18%, GST is ₹1,800 and the invoice total is ₹11,800.
How do I remove GST from an inclusive amount?: Divide the GST-inclusive total by one plus the rate as a decimal. At 18%, divide by 1.18. A ₹11,800 inclusive total therefore contains a ₹10,000 base and ₹1,800 GST.
When are CGST and SGST used instead of IGST?: A taxable intra-state supply generally splits the applicable GST equally into CGST and SGST. A taxable inter-state supply generally uses IGST. Place-of-supply and registration rules can be nuanced, so confirm unusual cases with a qualified tax adviser.
Does receiving an invoice through UPI change the GST rate?: No. UPI is a payment method. GST treatment follows the underlying goods or services, supplier and recipient locations, registration status, exemptions, and current classification—not whether the customer paid by UPI.
Which SAC code should an Indian SaaS business use?: There is no universal SaaS code independent of the actual supply. CBIC classifications include 998313 for IT consulting and support, 998314 for IT design and development, and 998315 for hosting and infrastructure provisioning. Match the contract and invoice description with professional advice.

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