GST Calculator
Calculate GST — add it to a price or extract it from a GST-inclusive total.
How to use GST Calculator
- Enter the amount and select your GST rate (18% for most Indian services, 10% Australia, 15% NZ).
- Tell it whether the amount includes GST — that decides add vs extract.
- Read the three-way split: base price, GST amount, total.
- For Indian intra-state invoices, halve the GST into CGST + SGST lines; inter-state shows it as IGST.
What is GST Calculator?
A GST calculator handles Goods and Services Tax in both directions: exclusive → inclusive (price × (1 + rate): ₹1,000 at 18% GST → ₹1,180) and inclusive → exclusive (total ÷ (1 + rate): a ₹1,180 GST-inclusive price contains ₹1,000 base + ₹180 tax).
GST is the consumption tax of India (slabs of 5%, 12%, 18%, 28% by goods category), Australia (flat 10%), New Zealand (15%), Singapore (9%) and Canada (5% federal, plus provincial layers). The reverse calculation is the everyday one — prices are typically quoted GST-inclusive, and invoices, returns and expense claims need the split.
About the GST Calculator
Enter an amount and GST rate, choose whether the amount includes GST or not, and get the base price, GST amount and total — the exact split invoices and GST returns require.
India-specific notes the calculator's math supports: the 18% slab covers most services, 5%/12%/28% cover goods categories; on intra-state sales the GST splits evenly into CGST + SGST (an 18% invoice shows 9% + 9%), while inter-state sales carry it as single IGST — same total, different boxes on the return. Australia's shortcut is worth knowing: at exactly 10%, the GST inside an inclusive price is one-eleventh of the total ($110 inclusive → $10 GST).
Business users live in the reverse direction: registered businesses claim input credits on GST paid, so every expense receipt needs its GST extracted — divide by 1+rate, never subtract the percentage, or every claim runs slightly wrong.