GST Calculator

What is GST?

Goods and Services Tax (GST) is an indirect tax levied on the supply of goods and services in India. Introduced on July 1, 2017, it replaced multiple cascading taxes and unified the Indian market under a single tax structure.

GST Tax Slabs in India

GST in India is structured under four primary tax slabs:

Slab	Goods & Services Covered
5%	Essential items: food grains, medicines, transport services
12%	Processed food, business class air travel, mobile phones
18%	Most services, electronics, computers, capital goods
28%	Luxury goods, automobiles, aerated drinks, tobacco

How GST is Calculated

Adding GST (Exclusive):

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

Removing GST (Inclusive):

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

CGST and SGST Breakdown

For intra-state transactions, the total GST is split equally between:

• CGST (Central GST) — collected by the Central Government
• SGST (State GST) — collected by the State Government

For inter-state transactions, IGST (Integrated GST) applies instead.

How to Use the GST Calculator

Use the calculator in two common situations:

1. Add GST when you know the base price and want to find the invoice amount.
2. Remove GST when you know the final price and want to find the pre-tax value.

For example, if a service costs ₹10,000 before tax and GST is 18%, GST is ₹1,800 and the final invoice value is ₹11,800. If ₹11,800 is already inclusive of 18% GST, the base value is ₹10,000 and GST is ₹1,800.

GST Inclusive vs Exclusive

Mode	Use when	Formula
Add GST	Base price is known	Base Price x GST Rate
Remove GST	Final price is known	Final Price / (1 + GST Rate)
Split GST	Intra-state sale	CGST + SGST
IGST	Inter-state sale	Full GST as IGST

Common GST Mistakes

1. Applying GST twice on an already inclusive price.
2. Confusing CGST/SGST split with extra tax.
3. Using the wrong slab for mixed goods or bundled services.
4. Ignoring rounding differences in invoices.
5. Treating GST collected as income instead of tax payable.

Frequently Asked Questions

What is GST inclusive price?

GST inclusive price means the final price already contains GST.

What is GST exclusive price?

GST exclusive price is the base amount before GST is added.

Is CGST plus SGST extra?

No. CGST and SGST split the same GST amount for intra-state transactions.

Which GST rate should I use?

Use the rate applicable to your product or service category. Check official GST classification for business decisions.

Can this calculator be used for invoices?

Yes, it can estimate invoice values, but businesses should still verify tax rates, HSN/SAC classification, and compliance rules with their accountant.