How the gst calculator works
Adding GST to a base amount:
GST amount = Base amount × (rate / 100)
Total = Base amount + GST amount
Total = Base amount + GST amount
Removing GST from a GST-inclusive amount:
Base amount = Total ÷ (1 + rate / 100)
GST amount = Total − Base amount
GST amount = Total − Base amount
CGST and SGST are typically split equally (half the total GST each) for intra-state transactions in India's GST system; inter-state transactions use IGST equal to the full rate instead.
Step-by-step guide
- Choose whether you're adding GST to a base price or removing it from a GST-inclusive price.
- Enter the amount.
- Select the applicable GST slab (5%, 12%, 18% or 28%).
- Read the base amount, tax breakup and total instantly.
Worked example
On a base amount of ₹10,000 at 18% GST: GST amount = ₹1,800 (split as ₹900 CGST + ₹900 SGST for an intra-state sale), giving a total invoice value of ₹11,800.
Frequently asked questions
For sales within the same state, GST is split equally between CGST (central) and SGST (state). For sales between different states, the full rate is charged as IGST (integrated GST) instead.
GST slabs (5%, 12%, 18%, 28%) are assigned by category under India's GST law — check your product's HSN/SAC code or your supplier's invoice for the applicable rate.
Yes, this calculator models India's CGST/SGST split. For a general sales-tax or VAT calculation elsewhere, only the total tax amount and total figures are directly comparable.