GST FAQ
Answers to the most common questions about GST calculation, rates, and using this website.
GST is a single indirect tax charged on the supply of most goods and services in India, replacing several older central and state taxes.
Multiply the amount by 18 and divide by 100 to get the GST, then add it to the original amount. The GST Add Calculator does this instantly.
Divide the GST-inclusive price by (1 + rate ÷ 100) to find the base amount, then subtract that from the total. Try the GST Remove Calculator.
CGST is the Central GST — the central government's half of the GST charged on an intra-state sale.
SGST is the State GST — the state government's half of the GST charged on an intra-state sale, equal in amount to CGST.
IGST is the Integrated GST charged on inter-state sales and imports, combining what would otherwise be CGST and SGST into a single tax.
Evenly. If the total GST rate is 18%, CGST is 9% and SGST is 9%.
A GST-inclusive price already has GST added to it — the number you see is the final amount a customer pays.
A GST-exclusive price is the base or taxable value before GST is added.
Apply the discount first to get the taxable value, then calculate GST on that reduced amount. The GST Invoice Calculator handles this automatically per line item.
Yes, every calculator on this site is fully responsive and works on phones, tablets and desktops.
No. GST Calculator India is an independent, informational website and is not affiliated with or operated by the Government of India or the GST department.
No sign-up, login or account is required. Every calculator is free and open to use immediately.
No. All calculations run locally in your browser using JavaScript — nothing you type is transmitted anywhere.
The quick-select buttons cover 0%, 5%, 12%, 18% and 28% — the common Indian slabs — plus a custom option for any rate from 0–100%.
Yes, use the GST Invoice Calculator to add multiple line items, each with its own quantity, discount and GST rate.
Check that you've entered a positive amount and selected a GST rate. The result updates automatically as you type.
Yes, use the Copy Result or Share buttons below any calculator to copy the summary or share it via your device's share menu.
Yes, use the Print button, which opens your browser's print dialog with a clean, print-friendly layout.
Once the page has loaded, calculations continue to work without an internet connection, since everything runs in your browser.
GST Add starts from a base price and adds GST on top. GST Remove starts from a GST-inclusive total and works backward to find the base price.
Calculations use standard GST formulas and are accurate to two decimal places (the paisa). Always verify results independently for compliance or filing purposes.
Yes, tap "Custom" on any calculator's rate selector and enter the exact rate you need.
The Invoice Calculator is for quick totals and quotes only. It doesn't include GSTIN, HSN codes or invoice numbering required for a statutory tax invoice.
Input Tax Credit lets a registered business offset GST paid on its purchases against GST collected on its sales, avoiding tax being charged repeatedly on the same value.
The GST Council, made up of central and state finance ministers, decides and periodically revises GST rates and classifications.
Yes, GST rates are set nationally by the GST Council and apply uniformly across states — only the CGST/SGST split changes based on where a sale happens.
No, every calculator on this site is completely free to use.
The underlying add/remove math works for any percentage-based tax, but the CGST/SGST/IGST split and rate slabs are specific to India's GST system.
Search your product's HSN or SAC code on the official GST portal, or check a recent supplier invoice. See our GST Rates guide for an overview of the slabs.
Yes, the GST Invoice Calculator applies a discount per line before calculating GST, matching how retailers usually bill.
Freelancers, small business owners, retailers, students and anyone who needs a quick, accurate GST calculation without spreadsheets.