TaxZeo
Sign InFree Trial

GST Calculator — Add or Remove GST

A quick, no-frills GST calculator for the two most common calculations CAs and business owners run every day: adding GST to a base price to get the invoice total, or working backwards from a GST-inclusive amount to find the base value and tax component. Select a standard rate slab, toggle between intra-state (CGST + SGST) and inter-state (IGST) supply, and get an instant breakdown.

Enter Amount

₹
Inter-state supply (IGST applies instead of CGST+SGST)

Calculation Result

Base Amount (excl. GST)₹10,000.00
CGST @ 9%₹900.00
SGST @ 9%₹900.00
Total GST @ 18%₹1,800.00
Total Amount (incl. GST)₹11,800.00

Reference

• Intra-state supply: GST is split equally into CGST + SGST (each half the total rate)

• Inter-state supply: the full rate is charged as IGST to the destination state

• Common slabs: 5%, 12%, 18%, 28% — verify the exact rate applicable to your product/service on the GST portal

How It Works

  1. 1

    Choose Add GST or Remove GST

    Use "Add GST" when you have a base price and need the invoice total, or "Remove GST" when you have a total and need to find the taxable value.

  2. 2

    Select the GST rate slab

    Pick 5%, 12%, 18%, or 28% based on the applicable rate for your product or service.

  3. 3

    Toggle intra-state vs inter-state

    The result splits into CGST + SGST for intra-state supply, or shows IGST for inter-state supply — live as you type.

Automate GST Calculations on Every Invoice

TaxZeo applies the correct CGST/SGST/IGST split automatically on client invoices — no manual math required.

Get Free DemoSign In →

Frequently Asked Questions

How do I add GST to an amount?+
Multiply the base amount by the GST rate percentage to get the GST amount, then add it to the base amount for the total. For example, ₹10,000 at 18% GST = ₹1,800 GST, giving a total of ₹11,800.
How do I remove GST from an inclusive amount?+
Divide the GST-inclusive amount by (1 + GST rate/100) to get the base amount, then subtract the base from the total to get the GST component. For ₹11,800 inclusive of 18% GST, the base amount is ₹11,800 / 1.18 = ₹10,000.
When do I charge CGST + SGST instead of IGST?+
CGST and SGST apply to intra-state supplies (buyer and seller in the same state), each charged at half the total GST rate. IGST applies to inter-state supplies (buyer and seller in different states) at the full rate, collected by the central government and apportioned to the destination state.
What are the standard GST rate slabs in India?+
The common GST rate slabs are 0%, 5%, 12%, 18%, and 28%, with some items also attracting a compensation cess on top of 28%. This calculator covers the four non-zero standard slabs — verify the exact applicable rate for your specific product or service on the GST portal.
Does this calculator apply to composition scheme dealers?+
No. Composition scheme taxpayers pay GST at a flat concessional rate on turnover (typically 1%, 5%, or 6% depending on the business type) rather than the regular rate-wise CGST/SGST/IGST structure this calculator models.

Related Tools & Resources